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Neurofibromatosis (NF1) affects 1/2500 people throughout the world. Children with NF1 require a multidisciplinary service ideally, delivered on a single site. NF1 is a very variable condition with children requiring the expertise of genetics, paediatricians, ophthalmologists, dermatologists, neurologists and other specialities as required. Building such a service concentrates expertise, facilitates coordination of care and fosters ideal opportunities for research. Aims: 1) To develop a service ensuring children had access to a multidisciplinary clinic on an annual basis. 2) Hold monthly clinics offering ophthalmology, medical, developmental and dermatology follow up. 3) To create a registry of patients which captures the incidence and prevalence of NF1 in Ireland. To offer best possible care for the children attending the service by following international consensus guidelines. 4) To liaise with NF1 Association, families and research authorities. Methods: 1) Appointment of a CNS/CNM2 in Neurofibromatosis as funded by the NCH Foundation. 2) Visit to the complex NF1 Clinic in Manchester’s Children’s Hospital and learn from their service, MDT and guidelines. 3) Establish links with genetics, oncology, radiology and orthopaedic depts. in OLCHC. 4) Create a referral pathway for HCPs to ensure children with NF1 are referred to most appropriate service in a timely fashion. 5) To register the service on Orphanet and gain entry into an ERN as a multi-site service in conjunction with OLCHC. Results/Conclusion: To date, the service has been running for 9 months. The CNM2 provides telephone service and coordinates clinics. The Clinic has been registered in Orphanet and the process has begun to create a patient registry and enter the service in the ERN., Germline mutations in the succinate dehydrogenase subunit genes SDHB, SDHC and SDHD are the most frequent causes of inherited phaeochromocytomas and paragangliomas. Patients presenting with these tumours are usually offered genetic testing for these and other genes as part of standard clinical investigations. However, the information regarding penetrance and phenotype genotype correlations associated with SDHB/C/D mutations is variable, making it difficult to determine an optimum management strategy for this group. In order to address this issue we undertook a retrospective cohort study of patients who underwent genetic testing for SDHB, SDHC or SDHD. 195 patients were identified through the Irish Genetics laboratory electronic database as having had a genetic test for SDHB, SDHC or SDHD and referral source, referral reason and genetic test outcome were analysed. Analysis of penetrance and phenotype presentation was determined through a Clinical Genetics chart review of 147 patients from 40 separate families. Analysis of age-related tumour risks according to relevant gene and mutation type (for SDHB and SDHD) provided estimates of penetrance and genotype-phenotype correlations. Increased knowledge of the molecular basis of phenotypic variability commonly observed in individuals with germline SDHB/C/D mutations will facilitate the development of age-appropriate management protocols based on gene specific tumour risks., Irish Travellers are an endogamous, ethnically Irish population of ~40,000. Consanguinity is common. Knowledge of Traveller disorders exists but mainly in specialised Irish centres. Most Traveller disorders are published but ethnicity is not explicit, hampering diagnoses, particularly if the patient is overseas where knowledge about this population is poor. Aims: To catalogue inherited Irish Traveller disorders through identifying the disorders, detailing mutations, use of coding, (OMIM, Orphacodes & ICD10), publications, and help develop a database to facilitate diagnoses. Methods: A literature review was undertaken. Key national and international Clinician/scientists were contacted to identify relevant disorders and publications. Laboratory and clinical databases were searched to retrieve disorders & mutations. Annotations were updated. An Excel database was established listing each disorder, its appropriate code, associated mutation and relevant publication. Results: 86 distinct rare genetic disorders resulting in 75 phenotypes were identified; 78/86 were autosomal recessive; 4 of these were dominant disorders presenting only in the recessive state. Seven dominant disorders with no recessive phenotype were included as > one affected individual existed. One common 17q12 duplication was included, presenting in two unrelated families. Homozygous mutations were found in all recessive disorders bar one. The genetic basis of 78/86 was established. A further 2/76 have common haplotypes; the genetic basis of six disorders remains unclear. Linkage disequilibrium was observed in 4 families with co-existing McArdles disease and microcephaly & 11 individuals have co-existing Friedreich’s ataxia & galactosemia. Conclusion: Our work is the first step towards cataloguing inherited Irish Traveller disorders. Future challenges include development of an online mutation database., Primary Trimethylaminuria (TMA)(OMIM 136132), is an autosomal recessive rare disorder which results in diminished capacity to oxidise the dietary derived amine trimethylaminuria to its odourless metabolite Trimethylamine-n-oxide (TMA-n-Oxide). Severe primary TMA has been defined as the percentage of unmetabolised free TMA in urine being >40% and mild/moderate TMA range is 10-39%. More than 30 variants of the Flavin monooxygenase 3 (FMO3) have been reported to cause primary TMA. Diagnosis of primary TMA has implications for management of the patient in relation to treatment and genetic counselling. We sequenced the entire FMO3 gene coding region in 10 patients who had a biochemical diagnosis of TMA made in the past 5 years. Three of the patients had severe TMAU (% TMA range 39.4 to 45), (Group A) and 7 had mild to moderate TMAU (%TMA range 10-30), (Group B). We identified causative (loss of function) in 5/10 individuals. Homozygosity for loss of function mutations was detected for 2/3 cases with severe TMAuria (Group A). 3/7 of the patients with mild to moderate TMAuria biochemically had a genetic diagnosis. Two were homozygous for Glu158Lys/ Glu308Gly and the other was compound heterozygous for P153L and A232T. Primary TMAU is rare in Ireland and mutational analysis should not replace biochemical diagnosis.The rate of detection of pathogenic mutations was low using the recommended biochemical cut-offs. The E305X mutation the first FMO3 mutation described in OMIM (136132.0001) in an Irish Australian family may be an Irish Mutation. Two new apparent FMO3 mutations are described in this Irish population. A cut- off of free TMA levels higher than that suggested on the Gene Utility card may be more beneficial in directing genotyping., Background: As part of the Irish Kidney Gene project, 2000 people with renal disease were surveyed and >30% of participants reported a family history for their condition. This strongly suggests an underlying genetic component for the development of kidney disease. Blood and urine tests as well as kidney biopsies are frequently used to inform on aetiology of the disease. However, in around 10% of cases, aetiology is simply unknown, making it difficult for physicians to provide a clear diagnosis or prognosis to these patients. Aim: This project aims to utilise genomic sequencing to stratify patients with hereditary renal disease (HRD). In doing so we seek to aid clinical diagnosis, provide insight into pathogenesis and in some cases point to specific therapies. Methods: We developed a custom, targeted NGS panel for inherited kidney diseases which we have applied to 48 HRD patients. The panel includes 11 genes which are established causes of polycystic kidney disease, von Hippel Lindau syndrome, renal cysts and diabetes syndrome and Alport syndrome. The NimbleGen Heat-Seq kit was used for library preparation and samples were sequenced using an Illumina MiSeq platform at Beaumont Hospital. Data was analysed using a custom bioinformatics pipeline and variants were classified according to the ACMG guidelines. Results/Conclusions: To date, this panel has identified candidate pathogenic variation in a third of samples studied. Future work in this project will include the development of a larger targeted panel including >100 known renal disease genes., Breast cancer is the most common female malignancy worldwide. Up to 10% of cases are the result of an inherited monogenic mutation, while a further 25% appear in familial clusters. Only 30% of hereditary breast cancers are attributed to mutations in BRCA1 and BRCA2, identified as high-risk genes through linkage analysis. While BRCA mutational status is highly informative, and allows clinicians to modify surveillance, prevention and therapeutic strategies, the risk conferred by mutations in other genes is more difficult to define in light of variable penetrance. Next-generation sequencing has been rapidly evolving to advance testing sensitivity and throughput in a cost-effective manner. This progression has made multi-gene testing a practical option when looking to identify inherited mutation(s) in a clinical setting. However, current clinically available multi-gene panels generate many variants of unknown significance in genes that are presently not considered clinically useful. The aim of our study was to design a multi-gene panel to enable the detection of rare, probably pathogenic variants contributing to the susceptibility of breast cancer in an Irish population. An extensive literature review was conducted in order to generate a list of 282 genes with potential association to breast cancer. Targeted DNA enrichment and multiplexed next-generation sequencing was performed on a cohort of 167 samples from the west of Ireland. 90 breast cancer patients and 77 geographically-matched controls were included in this study. Bioinformatic analysis was performed following GATK best practices workflow. Variant data for our 282 selected genes will be presented and discussed., Increasingly accurate surveys of human health throughout the life course has led experts to propose that stresses on the developing child whilst in the mother’s womb can affect the individual’s health later in life. Such long-term effects on health are thought to be mediated by a semi-permanent trace on the genes called an epigenetic mark, mediated by processes such as DNA methylation. DNA methylation patterns may be altered by the mother’s diet, particularly folate – a key component in the DNA methylation cycle. Currently, mothers are recommended to supplement their diet with 400μg folic acid/day as a preventative measure against neural tube defects prior to/during the first trimester. However, there remains no clinical recommendation as to whether mothers should continue supplementation during the latter two trimesters and the potentially heritable effects. Thus, we analysed cord blood samples (n=93) from the Folic Acid Supplementation in the Second and Third Trimesters (FASSTT) randomised control trial for genome-wide DNA methylation. Offspring exposed to folic acid in later pregnancy had fewer highly methylated genomic regions and more intermediately methylated sites. Upon further interrogation, gene ontology analysis revealed these sites are enriched for genes associated with cognition and neurological system processes, and tissue analysis revealed enrichment of affected genes associated with the brain. Cognitive and psychosocial testing of the children at age 7 years, using standardised tests (WPPSI, TEIQue-CSF, RASP), showed that the children supplemented during pregnancy scored significantly higher for emotional intelligence, resilience and verbal IQ. Thus, this study offers a potential biological mechanism linking maternal folate levels with childhood cognition., Introduction: We previously identified the mitochondrial 10-formyltetrahydrofolate synthase enzyme, MTHFD1L, as a risk factor for human Neural Tube Defects (NTD). This association was further supported by a mouse model of mutant mthfd1l, that exhibited an NTD and was rescued with maternal formate supplementation. The abundance of MTHFD1L is also increased in a range of cancers. MTHFD1L performs the last step in mitochondrial one carbon metabolism to produce formate for transport into the cytoplasm. Aim: Given the pivotal role of MTHFD1L in human disease, we sought to decipher the cellular response to the expression level of MTHFD1L in HEK293 cells. Methods: Human MTHFD1L was overexpressed in a stably transfected line using a pcDNA3.2 vector and knocked down using two inducible shRNA constructs that were clonally selected. Cells were grown and sampled over a five-day period. Expression level was confirmed by RT-qPCR. Intracellular and media formate levels were measured using GC-MS. Proteomics analysis was performed on whole cell lysates using LC-MS/MS on an Ultimate 3000 nano LC system coupled to a LTQ Orbitrap XL. Results: Intracellular and media formate levels directly correlated with expression level of MTHFD1L compared to controls within an approximately 1.5 to 3 fold range. Our proteomics analysis showed that MTHFD1L expression level had an effect on proteins involved in DNA synthesis, replication and repair. Discussion: We have demonstrated that MTHFD1L expression level has a direct impact on both intra- and extra-cellular levels of formate and may act as a signal for uncontrolled cell proliferation., Ireland has remained relatively isolated from mainland Europe, notwithstanding historical migrations including the Norse-Vikings, Anglo-Normans, and the British Plantations. Although previous studies have shown the Irish to have elevated levels of homozygosity compared to mainland Europe, the extent of genetic structure within Ireland, and the genomic impact of historical migrations, is largely unknown. Here we illustrate fine-scale genetic structure across Ireland that follows sociological boundaries and present evidence of admixture events into Ireland. Utilising the ‘Irish DNA Atlas’, a DNA cohort (n = 194) of genealogically described Irish individuals with four generations of ancestry linked to specific regions in Ireland, we analysed in combination with 2,039 individuals of regional British ancestry (the PoBI dataset) and show that the Irish population subdivides into 10 distinct geographically-stratified genetic clusters; three of shared British/Irish ancestry, and seven of predominantly ‘Gaelic’ Irish ancestry. This structure is remarkably homogenous, and is associated with very little gene flow barriers within Ireland. Additionally, using a reference of 6,760 European individuals and two ancient Irish genomes, we quantified the ancestry of these Irish clusters within the context of Europe as well as ancient Ireland. We show high levels of north-west French-like and Norwegian-like ancestry within Ireland, and homogenous levels of ancient Irish ancestry in our ‘Gaelic’ Irish clusters. Finally we detect admixture events into Ireland, coinciding with the Plantations of Ulster, as well as Norse-Viking activity within Ireland. Our work informs both on Irish history, as well as the study of Mendelian and complex disease genetics involving populations of Irish ancestry., Schizophrenia affects 1% of adults and is a major global health problem. I am interested in the potential role of the centrosome in schizophrenia. The centrosome, an organelle within cells, plays a crucial role in brain development where it directs cell shape, polarity and motility. The centrosome also seeds the growth of antenna-like signalling structures called primary cilia. Rare mutations in centrosome genes cause disorders that present with severe cognitive deficits and variable neuropsychiatric phenotypes. GWAS data has implicated many genes in schizophrenia. We have shown that seven schizophrenia risk genes encode proteins with centrosomal functions. Of these, SDCCAG8 is also associated with educational attainment in GWAS and the genome-wide significant SNPs for the two phenotypes are in high linkage disequilibrium indicating a pleiotropic effect. We have found that a schizophrenia risk SNP in SDCCAG8 is significantly associated with poorer performance in a social cognition task, in a large Irish dataset of schizophrenia patients and controls (p=0.001). To analyse the molecular function of SDCCAG8 we have used genome editing to knock it out in neuronal and retinal cells. Preliminary data shows that loss of SDCCAG8 impairs cells’ ability to make primary cilia and that their capacity to repair genome damage is reduced. Current work is addressing whether SDCCAG8 affects activities that may contribute to schizophrenia, including cell migration and cell signalling. This could identify molecular mechanisms by which SDCCAG8 mutations contribute to schizophrenia risk and cognition, and help uncover the processes that implicate centrosome genes in neurodevelopmental phenotypes., Multiple genetic loci have been identified for non-melanoma skin cancer (NMSC) in the general population. Polygenic risk score (PRS) was defined as the sum of all alleles associated with a trait weighted by the effect size of that allele as determined by a previous genome-wide association study (GWAS). We tested whether PRS, calculated using a GWAS of NMSC in a non-transplant population, can be used to determine risk of developing and time to NMSC post-transplant. Post-kidney transplant NMSC cases (n=155) and controls (n=442) were collected from Tennessee, Ireland and Scotland. Genetic variants that reached pre-defined levels of significance were chosen from a squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) GWAS, both conducted in non-transplant populations. Using these GWAS results, BCC and SCC PRSs were calculated at each p-value threshold (pT) for each sample. PRSs were tested as a predictor of case:control status using logistic regression and time to NMSC post-transplant in a survival model. SCC PRS calculated at pT 1x10-6 was the most significant predictor of case: control status of NMSC post-transplant (OR per 1 stdev increase in PRS=2.3; corrected P (Pc)=0.04). When NMSC was subdivided into SCC and BCC, SCC PRS pT 1x10-6 significantly predicted case:control SCC (OR=2.5, Pc=0.02) and BCC status (OR=7.6, Pc=0.02). SCC PRS pT 1x10-5 also significantly predicted time to BCC (Pc=0.007, HR=1.8) and SCC (Pc=0.05, HR=1.4). PRS of non-transplant NMSC can be used to predict case:control status of post-transplant NMSC, SCC and BCC as well as time to developing BCC and SCC post-transplant., Introduction: Rare diseases are diseases, which affect a small number of people compared to the general population. In Europe, a disease is considered rare when it affects no more than 5 per 10,000 individuals. A disease can be rare in one region but common in another. The objective of this study was to derive a proxy estimate the number of childhood onset rare diseases through referrals to the country’s only Genetics center, as the Republic of Ireland does not have a centralized rare disease registry. Methods: A retrospective review of referrals to cytogenetics and clinical genetics for the years 2000-2016 for patients born in the year 2000 was undertaken. Anonymized data was catalogued into rare, common, normal, likely rare & unclassifiable by review of records, and assigned Orphacodes based on diagnosis. Census live birth data was used as the denominator. Results: 54,7891 live births were recorded by the census in 2000. 1872 referrals to Genetics (representing 1749 individuals born in 2000) were retrieved for review. 1007 had cytogenetic testing only, of which 51 had rare chromosomal anomalies. Review of 742 referrals to clinical genetics yielded 581 with a rare disease (78%), 7 with a likely rare disease, 56 with a common disorder, 83 who were normal (at risk relative) & 15 unclassified (hadn’t yet been seen). Of the 53/1749 who had died (3%), 51 had a rare disease with congenital malformations (24) the most common cause., Neurofibromatosis type 1 (NF1) is a relatively common autosomal dominant genetic condition, with an incidence of around 1 in 3000. All NF1 patients attend our regional NF1 clinic intermittently and our departmental database records clinical details. Currently, we have 468 living patients affected with NF1 in Northern Ireland. NF1 is caused by mutations, or occasionally deletions, of the neurofibromin tumour suppressor gene, which leads to over-activation of the RAS-MAPK pathway, and tumour formation. These vary from benign lesions, such as neurofibromas, through to malignant peripheral nerve sheath tumours (MPNSTs) and tumours in other sites, particularly the central nervous system, that can be associated with significant morbidity and mortality. MEK inhibitors have recently been shown to be an effective treatment modality in the tumours associated with NF1. We have studied our population to determine the number of patients with plexiform neurofibromas, who are at risk of MPNSTs, and the proportions of patients with tumours elsewhere. This will allow us to identify which patients could benefit from MEK inhibitors in the future., Tuberous Sclerosis complex (TSC) is an autosomal dominant genetic condition which results, in the majority of patients, from a mutation in the TSC1 or TSC2 genes. Many of the patients are affected by angiomyolipomas and sub-ependymal giant cell astrocytomas. There is evidence that mTOR inhibitors, particularly Everolimus, shrink such tumours. In addition, the recent EXIST-3 study showed that Everolimus led to a significant reduction in seizure frequency in TSC patients whose seizures had previously proved resistant to anti-epileptic drug treatment. Consequently, a European licence has been granted to prescribe Everolimus for this indication. In order to determine the potential number of patients who may be eligible for consideration of this treatment, we undertook a complete population survey of epilepsy in our TSC patients. Information was extracted from our database and descriptive statistics were carried out. We were particularly interested in obtaining numbers of those whose seizures were poorly-controlled, defined as requiring 3 or more anti-epileptic drugs to manage their seizures, or requiring neurosurgical intervention. Many of the TSC patients with a diagnosis of epilepsy were also diagnosed with learning difficulties. The possibility of an association between degree of seizure control and severity of learning difficulties was explored. Finally, the annual cost of prescribing Everolimus to Northern Ireland’s TSC patients with poorly-controlled seizures was estimated., Charcot neuroarthropathy is associated with neurological deficit and is often seen in patients with a history of diabetes. Zygodactyly is a common congenital malformation with cutaneous webbing of the second and third toes. To determine the frequency of Zygodactyly in midfoot (tarso-metatarsal) Charcot neuropathy due to diabetes, we analysed a prospective series of twenty-five patients with Charcot neuropathy referred to podiatry clinics from diabetes and vascular departments. Twenty-nine patients with diabetes (but no Charcot neuropathy) were used as controls. Nineteen of the twenty-five patients with type 2 diabetes, peripheral neuropathy, and midfoot Charcot neuroarthropathy, exhibited Zygodactyly as did one of the twenty-nine controls. There was a significant difference between the two groups (Chi squared test p< 0.001). None of the cases or controls had any dysmorphic features or other limb malformations. Zygodactyly occurred in association with midfoot Charcot neuroarthropathy (diabetic neuropathy) in 76% of cases. No association between Zygodactyly, diabetes and Charcot neuropathy has previously been recognised. Genes such as OPG and RANKL affect foot and bone development and MSX1 and PLA2G6 affect spinal and distal nerve development. The possibility of a genetic contribution in patients who develop type 2 diabetes, peripheral neuropathy and Charcot neuroarthropathy must be considered. Zygodactyly may act as a predictive marker for Charcot neuropathy and further identification of regulatory genes may be possible. Until then, recognition of Zygodactyly may allow early intervention and a reduction of complications in patients with Charcot neuropathy., Development of an unusual clinical phenotype across both common and rare cancer types presents a significant challenge from a diagnostic and therapeutic perspective. We describe two distinct cases involving an Ovarian adenocarcinoma and a Medullary Thyroid cancer (MTC) patient and wherein both patients presented with metastases at highly unusual locations, followed by development of an aggressive disease. In first case involving a patient diagnosed with ovarian adenocarcinoma presented with a rare solitary extracranial brain metastases with no other associated metastases after 2 years post-hysterectomy and chemotherapy. Despite surgical removal of the metastatic lesion and stereotactic radiotherapy, the patient showed a further relapse at the initial as well as two additional extracranial regions. Our current analysis of whole-genome sequencing of primary tumour and extracranial lesion, reveal a remarkable difference in the genomic aberration landscape between the primary tumour and the metastases. In addition, we also identify several structural variants including novel gene fusions as well as gross chromosomal abnormalities, which could be potentially utilized as targets for treating this patient further. In the second case, whole-exome sequencing of primary tumour and bone-marrow metastases in the MTC patient identified three germline single nucleotide polymorphisms (SNPs) within the RET proto-oncogene that remained undetected using routine hospital genetic testing procedures. More importantly, we report for the first time in thyroid cancer on the occurrence of a “chromothripsis-like pattern”, which involved shattering of chromosome 4 leading to complete abrogation of normal chromosomal function, along with dramatic widespread copy number aberrations across both primary tumour and bone marrow samples. These results provide a rationale for the application of comprehensive genomic analysis of cancers presenting with unusual and aggressive phenotypes to facilitate more appropriate therapeutic options and diagnoses., Transient Neonatal Diabetes (TNDM) is characterised by diabetes that develops in the first 6 weeks of life and resolves by 18 months. Approximately 70% of cases are classified as TNDM Type-1 (TNDM1), caused by methylation defects on chromosome 6q24. It is associated with some congenital anomalies, however associated hepatobiliary abnormalities are not described. Choledochal cysts are congenital dilations of part or all of the bile duct, occurring in 100,000-150,000 live births. The 5 major types are classified according to the extent of hepatobiliary involvement. Surgical excision of the cyst is indicated to prevent complications such as stone formation, malignancy, cyst rupture and pancreatitis. We describe a case of TNDM1 due to whole chromosome paternal uniparental disomy 6, with co-existence of a type 1a choledochal cyst in a female born following intrauterine growth retardation. Hyperglycaemia soon after birth led to insulin treatment and a diagnosis of TNDM1, with resolution of the diabetes by 4 months of life. Follow up of antenatal findings of a cystic anomaly demonstrated the presence of a type 1a choledochal cyst on ultrasound and magnetic resonance cholangiopancreatography. Sucessful surgical excision of the cyst and a roux-en-Y hepaticojejunostomy was undertaken at 6 months of age. To our knowledge the co-existence of these disorders has not previously been reported. Further genetic analysis by whole exome sequencing is now in progress to determine if a mutation in the PKHD1 gene, unmasked by the paternal UPD of the entire chromosome 6, explains the associated choledochal cyst in this case., Mosaic mutations can go unnoticed, underlie genetic disease or normal human variation, and may be transmitted as constitutional variants to future generations. Marfan syndrome (MFS) is a clinically variable systemic connective tissue disorder involving ocular, skeletal, and cardiovascular systems. The risk to siblings of an identified de novo variant in a proband remains above population risk but less than the 50% risk attributed probands (~75%) who have an affected parent. This is due to somatic and germline mutations reported in rare cases. We describe the phenotypic variability in three siblings with a confirmed heterozygous pathogenic exon 52 fibrillin1 (FBN1) gene variant with clinically unaffected parents Parental leucocyte DNA was tested and did not identify the FBN1 gene variant. Paternity has been unequivocally confirmed and subsequent testing of parental buccal samples failed to detect the variant. One brother had aortic valve replacement and aortic aneurysm repair at 35 while another brother had surgery of aortic dilatation at the sinuses of Valsalva at 32. The brothers had variable joint hypermobility, patellar dislocations and ophthalmic presentations involving subluxed lenses, myopia and ambylopia. Early onset of varicose veins as a teenager in one and thoracolumbar scolosis in another brother were present. Their 42 year old sister has apparently normal aortic and cardiac imaging and ophthalmology but has mild Marfanoid facial features. To our knowledge this is the first reported family in the literature of 3 siblings as a result of parental mosaicism for a FBN1 gene variant and highlights the impact for genetic counselling., The inherited retinal degeneration (IRD) patient cohort used in the study has been obtained via a collaborative network of opthamoloogists whereby if an IRD is suspected given consent, a DNA sample is taken and provided to a central laboratory for genetic analysis. The study seeks to detect previously identified, together with as yet undiscovered, pathological mutations in a panel of known retinal degeneration genes utilizing target capture next generation sequencing (NGS) for 264 IRD genes. The study to date includes over 700 IRD patients from more than 500 pedigrees. While clinical trials are in progress for patients with IRDs, many such trials require patients to have a known causative mutation to participate in these trials. The Target 5000 research project aims to genetically characterise the estimated 5,000 people in Ireland with IRDs. To date, as part of Target 5000, over 10% of the Irish IRD population has been sequenced providing real insights into the genetic architecture of IRDs in Ireland. Target 5000 offers not only a chance to discover new relevant and pathogenic mutations, but is vital to providing patients with information regarding the underlying genetic pathogenesis of their disease. Thus far, during the course of the study, genetic analysis of IRD patients has helped to resolve ambiguous phenotypes and to identify causative mutations in approximately 60% of IRD cases. The growing body of data from NGS studies of IRDs globally should facilitate better correlations between genotype and phenotype and refine methods for diagnoses and prognoses., Overgrowth syndromes are characterized by tall stature, macrocephaly and other congenital features. These disorders typically arise sporadically through de novo dominant mutations in a growing list of genes. Although whole-exome sequencing (WES) allows us to examine all genes at once in a cost effective manner, we are left with a very large number of possible disease-causing variants to sift through. In addition, we must identify at least two patients with mutations in the same novel gene for the finding to be significant. To address this, we utilized detailed phenotyping of patients with undiagnosed overgrowth to group patients with significant phenotypic overlap and to help us interpret and prioritize the variants identified via WES. We performed WES for 12 undiagnosed patients from our overgrowth cohort. For most patients, there were no obvious causative variants in genes that were previously associated with human overgrowth. Therefore we analysed the participants’ clinical records to look for phenotypic traits that may lead us to new candidate genes. After further mining of the WES data, we prioritized possible disease causing variants based on a number of factors including biological function of the gene, predicted effect on protein function and a minor allele frequency, Living the ‘high life’ presents challenging conditions of extreme cold, hypobaric hypoxia and a restrictive diet that forces populations to adapt to survive. The Quechua are an indigenous high altitude population of Peru and Bolivia. They have resided at altitudes greater than 2500 meters above sea level (m.a.s.l) for the past 10,000 years, following their arrival in South America. Previous studies have characterised their adaptive physiology and identified genes under natural selection (ref). However our understanding of their genetic adaptation to hypoxia is incomplete, as previous studies focused on common genetic variation and applied a limited number of selection tests. To shed further light on genetic adaptation in the Quechua, we established a cohort of 43 Quechua individuals from Cerro de Pasco, Peru (4330 m.a.s.l). We performed whole genome sequencing to a mean depth of 34X. We detailed the demographic history of Quechua using principal components analysis, Admixture and Treemix. We performed five tests of selection, (iHS, XP-EHH, ΔiHH, FST and ΔDAF) on real, and simulated Quechua data incorporating details of the demographic history of the population. We performed a composite of multiple signals (CMS), which aggregates information from the five tests of selection, and identified robust signals of positive selection in high altitude Quechua individuals. The Quechua appear as a relatively homogenous population, with 10% European ancestry. We report the top 1% of genes under selection identified by CMS. We identify putative hypoxia associated genes under selection as well as the previously reported well-characterised hypoxia gene EGLN1., DNA methylation is an important epigenetic mechanism of regulating gene expression that is affected in certain human diseases including imprinting disorders and cancer. In mouse, UHRF1 is an essential cofactor of DNMT1, the enzyme responsible for maintaining methylation patterns. To investigate the effects of loss of UHRF1 on methylation patterns in human cells, UHRF1 levels were decreased in immortalized hTERT fibroblast cell lines using short hairpin RNA. Genome-wide effects on methylation were investigated by the Illumina Infinium HumanMethylation450 BeadChip array. Online bioinformatics software tools were used to identify FDR-significant hypomethylated gene classes, which were then verified by pyrosequencing. Transcriptional effects on these gene classes were investigated by the genome-wide Illumina HumanHT-12 v4 Expression BeadChip array, and verified by RT-qPCR. While UHRF1 depletion caused widespread demethylation, the replication-dependent histone gene cluster and the cancer testis antigen genes were identified as most significantly hypomethylated in UHRF1 knockdown cells. Pyrosequencing confirmed hypomethylation in promoter regions of cancer testis antigen genes TSPY2, MAGEC1, MAGEC2 and MAGEA12, and histone gene HIST2H2AA4 in knockdown cell lines. Hypomethylation in these gene classes correlated with an increase in expression in the knockdown cell line. In addition, cells were rescued using UHRF1 cDNA and showed a return to wild type transcription levels in the rescue cell line. We have shown that these genes are regulated by promoter DNA methylation, confirming the sensitivity of cancer-testis genes to demethylation, supporting possible use of methyltransferase inhibitors to boost antigen presentation in cancers, and the crucial role of UHRF1 in cell cycle regulation., X-linked Retinitis Pigmentosa (XLRP) is a severe, early-onset form of inherited retinal degeneration (IRD). It is estimated that approximately 15% of XLRP cases are due to mutations in RP2 (Retinitis Pigmentosa 2). The ubiquitously expressed RP2 protein is involved in ciliary trafficking of lipid-modified proteins – a process vital for photoreceptor function and survival. Most pathogenic RP2 mutations are suggested to result in truncation or complete loss of the protein. The most common stop mutation, R120X, appears to trigger nonsense-mediated decay of the transcript. RP2 is therefore an excellent candidate for gene augmentation therapy. In recent years, personalised cell models have emerged as invaluable tools for the elucidation of disease pathogeneses and have greatly enhanced pre-clinical proof of concept studies. Through the Target 5000 programme, a project focused on genetic characterisation of the 5,000 IRD patients in Ireland, a male patient harbouring the R120X RP2 mutation was identified. A patient-derived dermal fibroblast cell model of the disease was thus generated and characterised. The transduction efficiencies of AAV vectors of various serotypes in fibroblasts were tested and compared, after which it was decided to proceed with an AAV2/2.CAG.RP2 vector to explore RP2 delivery in this patient-derived cell model. In addition, the effects of RP2 overexpression in vivo in murine photoreceptors and retinal pigment epithelium cells were analysed., Mitochondrial dysfunction leads to a lack of energy production and ultimately the death of the cell. Recently a number of disorders have been shown to have mitochondrial dysfunction including but not limited to; Multiple Sclerosis, Parkinson’s and Leber’s Hereditary Optic Neuropathy (LHON). In LHON, Complex I of the Electron Transport Chain (ETC) is affected which leads to a severe shortage of energy in the cell and eventually cell death. In particular retinal ganglion cells (RGCs) are affected, leading to retinal dysfunction and blindness. These observations have prompted interest in exploring innovative therapeutics to modulate mitochondrial disorders involving complex I deficiency. The team has explored candidate gene therapies for complex I deficiency, which could classically be delivered via Adeno Associated Viruses (AAV) such as AAV serotype 2 (AAV2), among other vectors. As such the team has developed novel in vitro methods for the analysis of complex I deficiency and the evaluation of novel candidate therapies, allowing us to monitor the efficacy of these therapeutics. Assays include a suite of methods to enable evaluation of Complex I activity and oxidative phosphorylation efficiency among other mitochondrial biomarkers. Such assays in principle would be of value for future in vitro and or in vivo studies involving therapies directed towards targeting complex I deficiencies., Background: Imprinted loci are paradigms of epigenetic regulation and are associated with a number of genetic disorders in human. A key characteristic of imprints is the presence of a gametic differentially methylated region (gDMR). Previous studies have indicated that DNA methylation lost from gDMRs could not be restored by DNMT1, or the de novo enzymes DNMT3A or 3B in stem cells, indicating that imprinted regions must instead undergo passage through the germline for reprogramming. However new putative gDMR have recently been described, along with an improved delineation of the existing gDMR locations. We therefore aimed to re-examine the dependence of methylation at gDMRs on the activities of the methyltransferases in mouse embryonic stem cells (ESCs). Method: We examined the most complete current set of imprinted gDMRs that could be assessed using quantitative pyrosequencing assays in two types of ESCs: those lacking DNMT1 (1KO) and cells lacking a combination of DNMT3A and DNMT3B (3abKO). Results: Loss of methylation was approximately equivalent in both cell types. 1KO cells rescued with a cDNA-expressing DNMT1 could not restore methylation at the imprinted gDMRs, confirming previous observations. However, nearly all gDMRs were remethylated in 3abKO cells rescued with a DNMT3A2 expression construct (3abKO + 3a2). Transcriptional activity at the H19/ Igf2 locus also tracked with the methylation pattern, confirming functional reprogramming in the latter. Conclusions: DNMT3A/B plays a vital role in methylation maintenance at imprints as the rescue with DNMT3A2 can restore imprints in these cells. This provides a useful system to explore factors influencing imprint reprogramming., SATB2, BCL11B and GATAD2A map to regions containing genomewide significant SNPs for schizophrenia and regulate key stages of neurodevelopment via epigenetic mechanisms. SATB2 mediates the projection of neurons across the cerebral hemispheres by regulating the activity of BCL11B via the NuRD nucleosome remodelling complex, which contains. GATAD2A. We hypothesized that genes within the NuRD complex and genes regulated by SATB2 in the pre- and post-natal brain may contribute to schizophrenia etiology. To test, we developed three gene-sets. 1.)Genes reported in mouse knockout studies of SATB2 during cortical development (SATB2_ Cortical). 2.)Genes mapping to SATB2 ChIP-seq peaks generated from mouse cortices at E15.5 (SATB2_Pre-natal). 3.)Genes mapping to SATB2 ChIP-seq peaks generated from mouse P0 hippocampal neurons (SATB2_Post-natal). We performed competitive gene set analysis (GSA) using MAGMA to test if genes within a gene-set were more strongly associated with schizophrenia than other genes in the genome. We applied GSA to schizophrenia GWAS (n=150,064). We also investigated these gene-sets for a genetic contribution to educational attainment (EA; proxy for cognition) using GWAS (n=405,072). After multiple test correction, we observed significant associations for (1)SATB2_Cortical with schizophrenia (P=8.65x10-05) and EA (P=0.00049), (2)SATB2_Pre-natal with EA (P=0.0068) and (3)SATB2_Post-natal with schizophrenia (P=0.0069) and EA (P=2.03x10-06). Further GSA established that effect sizes are stronger for these gene-sets when analysis is limited to genes that are highly expressed in neurons or at different key timepoints during neurodevelopment of the cortex or hippocampus. These data support a role for the NuRD complex and genes regulated by SATB2 in schizophrenia and EA, Background: Dacogen (5-aza-2’deoxycitidine) is currently used to treat Acute Myeloid Leukaemia (AML) and is in trials for myeloid dysplastic syndrome and some solid cancers. As a hypomethylating agent it is thought to act by inhibiting the enzymes which add methyl groups to DNA, chief among them DNMT1. Improved targeting has been hindered by a lack of understanding with respect to the exact mechanism of action on DNMT1 and of the gene targets affected by altered methylation following treatment. Methods: We performed a comparative treatment of the same normosomic, non-transformed fibroblast cell line hTERT1604 over three days with either pharmacological 5-aza-2’deoxycitidine (Dacogen) or with SMARTpool siRNA directly targeting DNMT1. DNA was collected for analysis of methylation levels using Illumina 450k BeadChip methylation arrays. Data was analysed in R using the tailored RnBeads pipeline and in-house scripts. Results: Both Dacogen and DNMT1 siRNA caused overall hypomethylation in the treated cells, with the latter proving more efficient at demethylation at genes in particular. Amongst the targets experiencing demethylation, some hypomethylated promoters were unique to Dacogen treatment and therefore off-target with respect to the reduction in DNMT1. However an unexpected phenomenon almost exclusively caused by 5-Aza-2’-deoxycytidine treatment was gain in methylation. Therefore we also compared our findings to an independent published 450k dataset of Dacogen treated AML cells (KG1a). Our results suggest Dacogen is also having an important effect on methylation unrelated to the inhibition of DNMT1 thus suggesting further avenues for therapeutic improvements., Disruptive, damaging ultra-rare variants (dURVs) are more abundant in schizophrenia (SZ) patients than controls and are more concentrated in neuronally-expressed genes with synaptic functions. dURVs in highly constrained genes influence educational attainment (EA; a proxy for cognition) in the general population. We used MAGMA to perform gene set analysis of the largest available GWAS datasets to investigate if association signals for SZ and EA similarly mapped to highly constrained genes and to neuronally-expressed genes with synaptic functions. We investigated if SZ and EA associations were enriched in brain regions at different timepoints from early development through to adulthood. Highly constrained genes (probability of being loss-of-function intolerant; pLI>0.9; n=3,230) are strongly enriched for association with SZ(p=3.14E-08) and EA(p=1.27E-09) in comparison to genes under less constraint (0.1, Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease affecting 45,000 people in Ireland. Prolonged joint inflammation results in tissue damage with consequent reduced functional capacity and quality of life. Damage to the joints of hands and feet, assessed by x-ray, is an important outcome measure that has genetic input of around 60%. Recent studies have identified single nucleotide polymorphisms (SNPs) in immune-related genes that are associated with severity of tissue damage in RA. One of our studies identified an association with C5orf30, a previously uncharacterized regulator of tissue damage and inflammation (1, 2). However a more comprehensive genome wide analysis is required to more fully characterize the genetic basis of RA severity. This project will identify genetic variants, and their synergistic combinations, that are associated with severity of RA. We will analyse genomewide SNP data in 1,007 RA patients using state-of-the-art genetic epidemiology and computational techniques, including negative binomial modelling, to identify variants linked with joint damage severity. The study population is uniquely large and detailed clinical and genetic datasets will be used for validation studies using five European early RA cohorts. Simulations for statistical power indicate excellent power will be achieved for moderately frequent alleles, for effect sizes (IRR) over 1.4. The aim is to develop both a genetic prognostic score for RA, and to identify novel mediators of tissue destruction. The earlier identification of RA patients at risk of poorer outcome would facilitate patient stratification and inform therapeutic targeting with more aggressive regimes whilst avoiding such treatment in patients likely to have a better outcome, Bloodstream infection and sepsis are often instigated by the bacterium Staphylococcus aureus. Upon accessing the bloodstream, S. aureus binds to the endothelium triggering vascular leakage, inflammation and oedema. These characteristics are difficult to treat pharmacologically as the nature of signalling guiding this host response remains unclear. microRNAs (miRNAs) regulate ~60% of the human genome through post-transcriptional silencing/ degradation of target genes. Previously, bacteria were shown to profoundly affect miRNA expression via up-regulation of dendritic miR-99b elicited by M. tuberculosis infection. This study investigates contributions of S. aureus induced endothelial miRNA dysregulation to sustained and excessive host responses in sepsis. Sheared (10dynes/cm2) human endothelial cells were treated with plasma and TNFα to mimic sepsis conditions. Infection induced miRNA alterations were uncovered using Taqman cards to generate miRNA profiles of uninfected and infected cells (RQ = 2-ΔΔCt). Potential mRNA targets were established bioinformatically and confirmed by RNAseq, western blots and qPCR. Following infection, 58 endothelial miRNA were significantly downand 35 significantly up-regulated, including miR-330 (p, DNA methylation is a critical mechanism for regulating gene expression and ensuring genomic stability. However, loss of function mutations of methyltransferase enzymes such as DNMT1 in normal differentiated cells result in a lethal phenotype. Consequently, existing investigations have only assessed DNMT1 knockdowns in embryonic stem cells or cancer cell lines. Here, isogenic lines of hypomorphic, normal, immortalised fibroblasts have instead been generated via stable integration with short hairpin RNA. Enrichment analysis of epigenome-wide methylation arrays indicated widespread demethylation within promoter and gene body regions. In addition, four specific gene categories were highlighted as most affected; protocadherins, genes regulating body mass, olfactory receptors and cancer/testis antigens. Comparison of short-term siRNA and long-term shRNA-mediated depletion of DNMT1 indicated that many regions recover methylation as shRNA-containing cell lines adapt to lowered levels of DNMT1. Interestingly, polycomb-regulated genes are refractory to de novo DNA methylation in these cells following recovery, reinforcing the concept of mutually-exclusive domains that are regulated by these two major epigenetic mechanisms., Background: The MTHFR C677T is a common polymorphism of the folate metabolising enzyme methylene tetrahydrofolate reductase (MTHFR) associated with hypertension. Riboflavin is a cofactor to MTHFR in the one-carbon cycle for generating methyl groups important for biological reactions such as DNA methylation. Supplementation with riboflavin has previously been shown to reduce blood pressure specifically in individuals with the homozygous MTHFR 677TT genotype. The mechanisms underlying the blood pressure lowering effect of riboflavin are currently unknown however aberrant DNA methylation has been implicated in the development of hypertension. The aims of this study were to examine global DNA methylation on hypertension in adults stratified by MTHFR genotype and in response to intervention with 1.6mg/ day of riboflavin in individuals with the MTHFR 677TT genotype. Methods: Stored peripheral blood leukocyte samples from participants who had consented and participated in targeted RCTs at Ulster University’s Nutrition Innovation Centre for food and HEalth (NICHE) and previously screened for the MTHFR C677T polymorphism were accessed for this study. Bisulphite conversion and pyrosequencing was used to analyse global and gene-specific DNA methylation. Results: Preliminary results show that methylation at the repeat element, LINE-1, and imprinted gene, IGF2 was not significantly different between the MTHFR C677T genotypes at baseline. However, subsequent supplementation with riboflavin resulted in a decrease in global methylation and an increase in IGF2 methylation in MTHFR 677TT participants. Conclusion: This is the largest study to date examining the interaction between the MTHFR C677T genotypes, riboflavin supplementation and DNA methylation. Riboflavin supplementation influenced repeat element and imprinted gene methylation in MTHFR 677TT genotype individuals. Further work will provide insights into the mechanism of riboflavin action in lowering blood pressure in these genetically at risk adults., Background: microRNAs are small, non-coding RNAs which are potentially valuable markers of cardiovascular disease (CVD) risk, including hypertension. This novel investigation aims to profile circulating serum concentrations of microRNAs in premature CVD patients to identify microRNAs that correlate best with hypertension. Methods: Serum samples from an existing cohort of 75 premature CVD patients were analysed for expression of 68 CVD-related microRNAs. Patients had been screened for the methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T, a risk factor for hypertension. Samples had been collected at baseline and following intervention with riboflavin, co-factor for the MTHFR enzyme, as part of a placebo-controlled double-blind, randomized trial. The associations between miRNA expression and blood pressure at baseline and post-intervention were investigated. Comparisons of data between CC and TT MTHFR genotype groups, and in response to intervention, were assessed using ANOVA, Pearson’s correlation and corrected t-test statistical analyses. Results: microRNA expression was successfully detected and quantified in all samples. At baseline miR-199a-5p expression was inversely correlated (r=-0.51;p, Background: Hypoxia in prostate tumours has been associated with disease progression and metastasis. MicroRNAs are short non-coding RNA molecules which are important in several cell processes, but their role in hypoxic signalling is still poorly understood. miR-210 has been linked with hypoxic mechanisms, but this relationship has not been extensively studied in a prostate cancer setting. Therefore, in this study, we investigate the link between hypoxia and miR-210 in prostate cancer cells. Methods: In this study we have used prostate cancer models of hypoxia to investigate the functionality of miR-210. Expression levels of miR-210 have been measured by qPCR in in vitro and in vivo samples. Functional bioassays were used to examine its effect on prostate cancer cell behaviour. Target genes have been identified and bioinformatic analysis has been employed to investigate a clinical significance for miR-210 in prostate cancer. Results: miR-210 is induced by hypoxia in prostate cancer cells. Over-expression of miR-210 impacts upon target genes which in turn may affect cell proliferation. Data-mining of online repositories of clinical prostate sample data shows that miR-210 is significantly correlated with Gleason grade and other clinical markers of prostate cancer progression. Further in silico analysis of miR-210 cellular networks reveal that miR-210 plays a key role in a number of important cell processes, the dysregulation of which can promote the development of prostate cancer. Conclusions: We propose that miR-210 is an important regulator of cell response to hypoxic stress and may play an important role in the pathogenesis of prostate cancer. Further study will focus on determining its function in prostate cancer and its potential as a biomarker in this disease.

Behcet’s disease (BD) is a complex, multifactorial rare disease, which is poorly understood. Genetic and environmental factors contribute to BD, but the process of diagnosis is challenging with inconsistent clinical manifestations. A recent survey of individuals living with rare disease(s) in Northern Ireland revealed ~50% of individuals receive ≥1 misdiagnosis with 1/20 seeing >10 doctors. Individuals with BD report a range of symptoms, which are variable in onset, severity, and frequency for this systemic vasculitis. Patients describe prolonged journeys to diagnosis with multiple healthcare professionals and medical specialties; there is no BD specialist in Northern Ireland. Using invitations via social media, voluntary groups, and direct contact we are using surveys incorporating micro-narratives, one-to-one semi-structured interviews, and focus groups to collect detailed family histories and stressor information to help characterise recurrent features in patients living with BD and their relatives in Northern Ireland. BD is most often reported in populations along the Silk Road. The highest prevalence is reported in Turkey at 20-420/100,000, compared 1.5/100,000 individuals in the UK. Mapping through general practitioners revealed a much higher than expected prevalence of 12.6/100,000 in the Northern Ireland population. Clusters were observed in Co. Down and Co. Antrim and plotted with social-demographic information. This high ‘UK’ prevalence and the identification of several families with multiple members diagnosed makes NI ideal to explore genetic and epigenetic risk factors for BD. This project involves deep phenotyping and strategies to improve recognition of Behcet’s disease, build collaborative partnerships, improve data collection, enhance training, and information sharing., The National Rare Disease Office (NRDO), initiated in June 2015, collates and disseminates Irish rare disease (RD) information. The prevalent nature of RD (1 in 16 of the population, approximately 80% of which has a genetic basis) and the burden to the health care system is under-recognised and a neglected public health issue. Awareness of rare diseases is a challenge, especially for GPs who each care for > 90 RD patients. The NRDO has made 58 presentations, lectures and publications and received numerous enquiries (58% of contacts from patients/ families, 25% from health care professionals and 4% researchers). Mapping Irish RD clinical and research expertise is developing through Orphanet Ireland. Enrolment of clinical expert centres has increased by 50%,but only, Aims To assess the tumour surveillance advice given to patients in Northern Ireland with confirmed PTEN hamartoma tumour syndrome (HTS). Methods We used the surveillance advice laid out by the Pan Thames Cancer Genetics Group in 2014 to benchmark our patients against. A coding search was carried out on our regional information management system to identify all patients with a confirmed diagnosis. The written/ electronic notes of these patients were reviewed. We adhered to the National PTEN audit inclusion criteria of including patients older than16 years, those with a pathogenic/likely pathogenic PTEN mutation or at 50% risk and those who had received advice between 01/08/10 - 01/08/2015. Results 21 patients were identified. All patients had a pathogenic PTEN mutation. 6 children were excluded. 1 adult was excluded due to lack of documented advice. 6 patients had a cancer diagnosis. 9 patients had a positive family history of cancer. Annual breast screening was recommended for 67% of patients which involved mammography in 83% and MRI in 17%. Annual thyroid USS and TFTs were recommended for 54% and 31% of patients respectively. 16% of female patients had gynaecology referrals completed. An annual dermatological review was recommended for 23% of patients. Widely variable colonoscopy and renal USS screening was recommended for 77% and 65% of patients respectively. No cases of Lhermitte-Duclos disease were identified vs 12% in the national UK audit. Conclusions There is a need for regional PTEN tumour surveillance guidelines to be produced and implemented through a regional PTEN specialist clinic., Catastrophic genomic alterations can drive unusually aggressive cancer phenotypes. We describe a diagnostically challenging rapidly fatal case of medullary thyroid carcinoma (MTC) occurring in a young, morbidly obese man presenting with diffuse bone marrow involvement and disseminated intravascular coagulation. Whole-exome sequencing and shallow whole-genome sequencing was carried out for the primary tumour and multiple metastases. We identified three germline SNP’s within the RET proto-oncogene which remained undetected using routine hospital genetic testing procedures. Indeed, one of the variants identified (L769L) has been previously reported in literature to be associated aggressive MTC presentation, yet remains untested for in the routine diagnosis of MTC. Supported by findings from shallow whole genome sequencing, we report for the first time in thyroid cancer, the occurrence of a catastrophic “chromothripsis-like pattern” (CTLP) event, which involved shattering of chromosome 4 leading to complete abrogation of normal chromosomal function, in addition to dramatic wide-spread copy number aberrations (CNA), across both primary tumour and bone marrow samples. We further describe the presence of loss-of-heterozygosity (LOH) in key genes involved in DNA repair mechanism pathways such as ATM, which possibly facilitated the CTLP event, in addition to LOH in other disease-associated genes such as ALK and NOTCH1 as key drivers of the aggressive and rapidly fatal clinical course in this patient and unresponsiveness to the standard-of-care targeted agent chosen. Given a possible rapid generation of tumor neo-antigens as a result of the CTLP event, immunotherapy may have been more suitable as a treatment option. Moreover, the presence of disease-associated SNP’s within the RET proto-oncogene, support their inclusion as part of routine RET genetic testing for aggressive MTC cases. These results provide a rationale for application of comprehensive genomic analysis of cancers presenting with unusually aggressive behavior to facilitate more appropriate therapeutic options and diagnoses., The Target 5000 research project aims to provide genetic testing for the estimated 5,000 people in Ireland who have an inherited retinal condition. Many clinical trials are available for patients with sight loss, however, many such trials require patients to have their causative mutation identified in order to enter the trial. The objective of the study is to genetically characterise patients with inherited retinal degenerations (IRDs) in Ireland and in principle to make clinical trials more accessible to some Irish people suffering from sight loss. The study also seeks to identify previously undiscovered pathological mutations in a panel of known retinopathy genes evaluated utilizing target capture next generation sequencing (NGS). Thus far in the study, as part of Target 5000 roughly 10% of the Irish IRD population has been sequenced and the results obtained are encouraging. Target 5000 offers not only a chance to discover new causative mutations, but is vital in giving patients access to information regarding the pathogenesis of their disease. Over 50 novel mutations have been discovered, as well as some previously ambiguous phenotypes resolved. More precise matching of genotype with phenotype from this study and similar studies globally should start to enable clinicians to better formulate accurate future diagnoses and at times prognoses., MicroRNAs are understood to play a functional role within the establishment of epigenetic marks and are in turn under epigenetic control. Emerging evidence suggests microRNAs are vital for both kidney development and renal function. This study aimed to identify differential methylation affecting microRNAs in patients with end-stage renal disease (ESRD). Methylation status was determined for 485,577 unique CpG sites in 105 individuals with ESRD and 52 donor controls with no evidence of renal disease using the HumanMethylation450K BeadChip array (Illumina). Statistically significant associations (P, Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease characterized by rapid-onset loss of upper and lower motor neurones, resulting in progressive paralysis and death from respiratory failure. Schizophrenia is a neuropsychiatric disease with positive symptoms, negative symptoms and impairment over a range of cognitive abilities. We have recently shown that schizophrenia occurs more frequently than expected in the pedigrees of ALS patients, suggesting an aetiological relationship between both diseases. Using linkage disequilibrium score regression with summary statistics for GWAS of ALS and schizophrenia comprising over 100,000 unique individuals, we estimated the genetic correlation between ALS and schizophrenia to be 14.3% (95% CI 7.05-21.6; p = 1×10-4). Up to 0.12% of the variance in ALS was explained by schizophrenia polygenic risk scores (p = 8.4×10). We leveraged the apparent pleiotropic relationship between ALS and schizophrenia to identify five potential novel ALS-associated genomic loci at conditional false discovery rate < 0.01. Diagnostic misclassification in the schizophrenia cohort did not contribute significantly to our observations (BUHMBOX p = 0.94) and we estimated that 4.86% (2.47-7.13%) of ALS cases would need to be misdiagnosed as schizophrenia to observe our genetic correlation estimate under a true genetic correlation of 0%. Our results indicate that the lifetime risk for comorbid ALS and schizophrenia increases from 1 in 40,000 to 1 in 34,336, which would require an incident cohort of 16,488 ALS patients to observe epidemiologically. Our findings suggest shared underlying biology between ALS and schizophrenia which will direct novel approaches in research and therapeutic development., Background Imprinted genes are autosomal, but only expressed from one parental allele and are often clustered in small groups. They play an important role in the regulation of normal mammalian development. Differentially methylated regions (DMR) on each allele are important in regulating the genes, with marks being characterised as primary or secondary DMRs, depending on whether they are inherited from the germ cells or arise later, respectively. Imprinting disorders such as Prader-Willi Syndome (PWS) and Beckwith-Weidemann Syndrome (BWS) arise either from uniparental disomy or faulty DNA methylation. We wished to determine 1) which of the loci are most sensitive to loss of methylation 2) to more precisely define the sensitive regions and 3) determine what happens at primary versus secondary imprints. Methods Stable knockdowns of the maintenance methyltransferase DNMT1 were generated in hTERT-immortalised adult fibroblasts using shRNA. Genome wide methylation levels were assayed using the Illumina 450k BeadChip array and analysed using bioinformatic approaches. Results We found that 1) the imprinted loci varied extensively in their sensitivity to loss of methylation 2) the extended locus involved in PWS was particularly sensitive 3) that loss of methylation at primary DMR appears to drive gains in methylation at secondary DMR. Conclusion Our results point to a mechanistic link between primary and secondary DMR which may explain why imprints are difficult to reprogram in somatic tissues., Osteoarthritis (OA) is a degenerative joint disease that affects millions of people globally with no disease-modifying strategies yet available. Our understanding of the pathology of OA is inadequate and this impedes investigation of efficient diagnosis and treatment. To expand our understanding of the underlying cellular pathology of OA, we studied a monogenic condition, familial osteochondritis dissecans (FOCD), associated with a known mutation in the ACAN gene. Patients with FOCD develop early onset OA with multiple joint involvement. The objectives of the project were to investigate the cellular pathogenesis of FOCD by studying (a) chondrogenesis of patient-derived bone marrow-mesenchymal stem cells (BM-MSCs) and (b) induced pluripotent stem cells (iPSCs) generated from patient fibroblasts. Our findings revealed that the mutation resulted in a misfolded or unfolded aggrecan protein, which accumulated in the rough endoplasmic reticulum (rER) during protein production. The consistent accumulation resulted in ER stress throughout chondrogenesis. Moreover, the rER stress caused abnormal or disregulated global extracellular matrix (ECM) production and assembly. Importantly, ECM composition analysis indicated that the patient chondrocytes produced abundant amounts of OA-associated markers. Using patient-specific stem cell models, we have discovered a cellular pathogenesis of FOCD involving abnormal cell function and defective tissue formation, contributing to the OA phenotype., Aims The Irish Travellers are a nomadic population primarily found within Ireland and the UK. Consanguineous unions are common, and as a population they are socially and genetically isolated from the surrounding, “settled” Irish population. Previous low-resolution genetic analyses suggested a common Irish origin between the settled and the Traveller populations. It is not known, however, what is the extent of population structure within the Irish Traveller population, the time of divergence from the general Irish population, and the extent of autozygosity. Methods We recruited Irish Travellers from across Ireland and the UK. For inclusion, a participant had to have had at least three grandparents with a surname associated with the Irish Travellers. DNA was extracted from saliva samples, and genotypes were generated using the Illumina OmniExpress SNP genotyping platform. With this data, we investigated population structure using fineStructure, quantified the levels of autozygosity with PLINK, and estimated a time of divergence using a method based on Identity by Descent (IBD) segment sharing. Results We merged, cleaned, and analysed data from 42 Irish Travellers, 2232 settled Irish, 2039 British, 143 Roma Gypsies, and 931 individuals from 57 world-wide populations. We confirm an Irish origin for the Irish Travellers, demonstrate evidence for population substructure within the population, confirm high levels of autozygosity consistent with a consanguineous population, and for the first time provide estimates for a date of divergence between the Irish Travellers and settled Irish. Conclusion Our findings have implications for disease mapping within Ireland, and they additionally inform on the social history of the Irish Traveller population., Copy number variants at 16p13.11 have been described in association with a variety of neurodevelopmental disorders. While deletions of this region are perhaps better described, the clinical significance of the reciprocal duplication is less clearly defined. Phenotypes reported in association with the duplication include developmental delay, speech delay, behavioural difficulties and neurodevelopmental phenotype such as autism, schizophrenia and ADHD. However, the region appears to be subject to variable expressivity and incomplete penetrance. To date we have detected duplications of 16p13.11 in 5 probands using oligonucleotide array CGH. Of these patients 3 showed duplications within the typical ~1.5Mb duplication region while 2 patients had a larger ~2.8Mb duplication, encompassing all of the above region. The clinical phenotype of these patients will be described. Two of these patients have inherited the duplication from their mothers, one was a de novo finding and the inheritance of the others is currently unknown. One of the maternal duplication carriers are also known to have a phenotype. Our data provides further clinical information on the phenotypic features of patients with this syndrome and provides more evidence for the pathogenic nature of this duplication., Introduction Patients referred to the NI Regional Cancer Genetics Service for genetic counselling were sent a questionnaire to evaluate patient satisfaction. The questionnaire focused on satisfaction surrounding the referral process, waiting times and communication during and after the appointment. Method One hundred patients, whose episode of care was completed between November 2015 and June 2016, were sent an anonymised structured questionnaire by post. Patients were seen by a genetic counsellor for assessment of their family history of cancer, predictive testing and genetic mutation screening Results To date (23/06/2016) the questionnaire response rate is 34%. So far 91% have expressed satisfaction with the service that they received. Useful comments and observations have been feedback in the questionnaire to aid service improvement. Data collection will be completed imminently to allow for complete analysis. Discussion Useful data has been collected which reinforces the service currently being delivered by genetic counsellors whilst also highlighting areas of service development., Leber’s Hereditary Optic Neuropathy (LHON) is one of the most commonly inherited optic neuropathies and results in significant visual morbidity among young adults. 95% of LHON patients will present with one of three primary mitochondrial mutations; G3460A, G11778A and T14484C. We describe a novel real time diagnostic test to detect the three common mutations leading to LHON. The test uses a combination of multiplex allele specific PCR (ARMS PCR) in combination with high resolution melt curve analysis to detect the presence of the G3460A, G11778A and T14484C mutations. PCR primer sets were designed to produce a control PCR product and PCR products only in the presence of the 3460A, 11778A and 14484C mutations in a multiplex single tube format. Products produce discrete well separated melt curves allowing clear detection of the mutations. The test has proved to be robust, cost and time effective with the real time closed tube system taking approximately 1 hour to complete. This test provides a simple, robust, easy to read output that is both cost and time effective, thus providing an alternative method to individual endpoint PCR – RFLP, PCR followed by Sanger / pyrosequencing and next generation sequencing. It will also allow diagnostic laboratories to detect 95% of LHON causing mutations in a single tube assay allowing diagnostic laboratories to avoid costly NGS assays for the vast majority of LHON patients, thus allowing resources to be focussed on patients with unknown mutations requiring further analysis., Atherosclerotic coronary artery disease (CAD) is a progressive chronic inflammatory condition that can lead to Major Adverse Cardiac Events (MACE) such as heart attacks. Currently there is no definitive test to predict MACE risk. Tumour necrosis factor alpha converting enzyme (TACE), also known as A Disintegrin And Metalloproteinase 17 (ADAM17) is a membrane-anchored protein responsible for the ectodomain shedding of a variety of transmembrane proteins such as cytokines, chemokines, growth factors and their receptors. TACE has been linked to several major acute and chronic inflammatory diseases including atherosclerosis. The aim of this study was to investigate if TACE may be a valuable predictive biomarker for CAD and MACE risk. TACE levels were measured in the plasma of CAD patients including those with acute coronary syndrome (ACS) and elective patients attending the catheterisation laboratory for coronary angiogram. TACE levels were measured using ELISA and quantitative real time PCR. Levels were compared with control samples collected from apparently healthy individuals and a subset of patients with no CAD as evidenced by coronary angiogram. Other factors that might affect TACE detection were also measured including sample type and storage time. To date 207 consecutive CAD patients and 40 controls have been recruited to the study. Results demonstrate that CAD patients have higher levels of plasma TACE in comparison to controls. TACE protein levels were especially highest in those ACS and elective patients with a previous history of MACE. Results to date indicate that TACE may be a useful marker to predict disease progression and recurrent MACE in CAD patients., Introduction NRG1 (neuregulin1) is a candidate tumour suppressor gene. NRG1 encodes ligands for members of the ERBB family, and has been shown to be silenced by methylation in breast cancer1. Breast and thyroid cancers share some genetic loci (e.g. PTEN, STK11), and an increased risk of thyroid cancer has been noted in survivors of breast cancer2. A single nucleotide variant (C>G) in NRG1 (rs2439302), has been associated with increased risk of non-medullary thyroid cancer3. Aim Our aim was to investigate the association between rs2439302 in NRG1 and predisposition to thyroid and breast cancers in an Irish population. Methods A two-arm case-control study was undertaken. Patients with mutations in high-risk cancer susceptibility genes were excluded. Controls included adults with no personal or familial history of breast or thyroid cancers. Male controls were included in thyroid case- control analysis only. DNA was extracted from whole blood/buccal swabs by ethanol precipitation. Genotyping was performed using Taqman-based PCR. Results 257 patients with thyroid cancer, 518 with breast cancer and 367 unaffected controls were genotyped. Homozygous carriers of the variant were found to have an increased risk of thyroid cancer (OR1.89 (1.21-2.95), p=0.005), but risk for mono-allelic carriers was not significantly increased (OR1.27 (0.87-1.84), p=0.21). The presence of the variant was not associated significantly with breast malignancy for mono-allelic (OR1.31 (0.95-1.8), p=0.095) or biallelic mutation carriers (OR1.15 (0.76-1.73), p=0.51). Conclusion Homozygous carriers of the G allele were found to be at increased risk of thyroid cancer, but no association was observed between the variant and breast cancer., The UGT1A gene family encode (UGT) activity that facilitate the transfer of glucuronic acid to a range of xenogenous and endogenous substrates, the polar end products of which are better suited for elimination through urine and bile. UGT1A genes exhibit an inducible pattern of expression regulated through the activities of such nuclear receptors (NRs) as pregnane X receptor (PXR) farensoid X receptor (FXR) and liver X receptor (LXR) that form a complex interactive network of ‘sensors’ to facilitate the elimination of potentially harmful metabolites and exogenous toxins. We have previously reported that activation of vitamin D receptor (VDR) through both synthetic agonists and nutritionally derived ligands, can induce the expression of both phase I metabolic (CYP3A) and phase III transporter (ABCA1) genes. Little is known however, as to how activated VDR may impact upon the regulation of phase II genes such as UGT1A1. In this study we demonstrate that ligand-activated VDR can significantly enhance the expression of several members of the UGT1A gene family. With particular respect to UGT1A1, we identify within the proximal promoter region of this gene a functional vitamin D response element (VDRE) also recognized by PXR but distinct from previously established regulatory elements that mediate FXR and LXR signalling. Based upon our data, we propose a model for VDR and circulating levels of vitamin D as maintaining stable expression of phase II and functionally related genes as a means to provide baseline protection against the effects of toxic xeno and endobiotic metabolites., Depression is a complex disorder with multiple symptoms, including a persistent low mood, anhedonia and cognitive impairments, and is currently the third leading cause of global disability. The underlying pathophysiology of depression is poorly understood but a growing body of evidence supports an important role for the microbiome in the aetiology of depression and other psychiatric disorders. While much interest is currently focused on the role of the microbiome-gut-brain axis in brain physiology and neurochemistry, the importance of the oral microbiome has received little attention. The aim of this study is to characterise the oral microbiome in adults with severe depression versus matched controls with no history of the disease. To achieve this, participants were asked to complete an online validated mental health survey and to provide a saliva sample. We identified 46 individuals who met the DSM-V criteria for severe depression and 46 age and sex-matched controls with no history of depression. Bacterial DNA was extracted from the saliva samples and 16S rRNA surveys were conducted using next generation sequencing. Differences in the bacterial community composition of the oral microbiota between patients and controls were determined. Metagenomic analyses were conducted using machine learning and computational intelligence algorithms using the 16S RNA data to generate inferred metagenome feature sets. Charting the oral microbiome in depressed patients could therefore provide new insights into the development of the condition, and lead to the identification of novel diagnostic and therapeutic response biomarkers., The nuclear receptors (NRs) pregnane X receptor (PXR) and constitutive androstane receptor (CAR) modulate transcriptional networks that dictate the bioavailability of many endogenous and exogenous compounds such as steroid hormones and therapeutic drug compounds. Elucidating those factors that invoke PXR/ CAR activity has been important for understanding the genetic basis for both metabolic disease and inter-individual variations in drug response. PXR is most closely related to Vitamin D receptor (VDR) for which there is relatively little is known for how this NR may impact upon these same physiological processes. In this study, we employed enteric cell models and ex-vivo based human colon explants to examine how activated VDR may impact upon the expression of genes of a metabolism and transporter function. We find that in relation to PXR and other evaluated NRs, VDR is the most efficient and dominant receptor for induced expression of CYP2B6, CYP3A4/5 and ABCA1. We note that upon activation with the synthetic agonist EB1089, VDR will achieve striking and sustained elevated expression of CYP3A4 at mRNA, protein and enzymatic level suggesting the potential for selective metabolic gene targeting through ligand design. In addition, we report members of the UGT1A gene family to be novel VDR regulated genes, thus extending the known metabolic effects of vitamin D to also encompass expression of phase II (conjugating) genes. This study intimates that systemic vitamin D status and/or activating VDR ligands may have pharmacokinetic relevance to co-administered drug regimes., Ancient genomes are often typically analysed with regard to ancestry and physical phenotype. Less common is examination and identification of genetic diseases, primarily due to the very low numbers of samples sequenced and poor level of sequencing related to the difficulties in sequencing from ancient DNA. Here we present the results of analysing 21 ancient Irish genomes. The data were screened for a wide range of pathogenic genotypes and markers. Giving information for the potential effects and prevalence of certain conditions as well as the earliest known confirmation of their presence. Using records of the remains, we also examined if any displayed phenotypes correlated to identified diseases., Coronary Artery Disease is the largest contributor of CVD, the leading cause of death worldwide. It is caused by atherosclerosis, a build-up of cholesterol in the blood vessels and chronic inflammation. The NLRP3 inflammasome plays a critical role in the secretion of IL-1β, and there is significant evidence that it is involved in the pathogenesis of a number of inflammatory diseases including atherosclerosis. Recent studies demonstrate that particular cell surface receptors namely the scavenger receptor CD36 and the endocannabinoid receptor CB1 are involved in the activation and regulation of the NLRP3 inflammasome and they have also been implicated in the pathogenesis of atherosclerosis. The present study aimed to investigate expression and activation levels of the NLRP3 inflammasome, the CD36 and CB1 receptors in blood samples obtained from patients with atherosclerosis at very high risk of a Major Adverse Cardiac Event (MACE) such as a heart attack. The cell signalling processes involved in NLRP3 inflammasome activation were also investigated in a THP1 in vitro model of atherosclerosis. Results to date indicate increased expression of NLRP3 in patients at very high risk of MACE and also demonstrate that THP1 macrophages require both the CD36 and CB1 receptors for optimal NLRP3 expression in response to oxidized LDL. These preliminary findings provide an insight into the mechanism of action of the NLRP3 inflammasome in atherosclerosis and prompt further exploration of this protein complex and its regulatory receptors as potential targets for prognostic and or therapeutic development in the strive towards a more personalised approach to the management of coronary artery disease., Approximately 30% of patients with epilepsy are refractory to anti-epileptic drug (AED) treatment and continue to have debilitating seizures that severely impact upon their quality of life. Exome sequencing in encephs etc has illustrated the importance of de-novo variants in the pathogenesis of rare neurological disorders. However, the contribution of de-novo mutations to pharmacoresistance in adult epilepsy is uncertain. In this study we investigated whether a trio whole exome sequencing paradigm could be applied to identify genetic causes of chronic, refractory epilepsy. We selected adult patients (n=5) with onset of seizures after 5 years of age, had failed ≥6 AEDs and were still experiencing >4 disabling seizures per month. Patients were excluded if they had a potentially ‘explanatory’ lesion on MRI. Parents were exome sequenced to identify de-novo mutations and these were assessed bioinformatically for pathogenicity. We confirmed the presence of coding de-novo mutations that were bioinformatically predicted to be functional and damaging in 3/5 patients. One of these occurred in the gene DNM1L, which was recently implicated in pharmacoresistant epilepsy (Vanstone et al. EJHG, 2015;Nov 25). This represents a potential diagnostic yield of 20% however more data is required and more trios are currently being sequenced. We have demonstrated the potential diagnostic yield of whole exome sequencing in a small number of adult patients with chronic refractory epilepsy. Identifying genetic mutations underpinning this disorder may provide new insight into the underlying biology and offers the potential for therapeutic intervention in the form of precision medicine., IgA nephropathy (IgAN) is the most common form of glomerular nephritis worldwide1. Difference in incidences between ethnicities and familial inheritance patterns indicate this is a genetic disorder. An IgAN locus on chromosome 6q22-23 was identified via linkage analysis; however the causal gene remains elusive2. We set out to identify mutations underlying familial IgAN using whole exome sequencing. DNA was collected on 25 (unaffected and affected) individuals across 6 families with IgAN. Families were chosen on the basis of having at least 2 affected members with IgAN. We carried out full exome sequencing on 12 of the affected members from these families. Depending on the pattern of inheritance in a given family, mutations that fitted a dominant, recessive or compound heterozygote model of inheritance were screened for. These variants were then filtered based on being shared between affected individuals within a family, their minor allele frequency, region, function and predicted deleterious nature. We identified a number of potential candidate mutations in these families and including a mutation in the gene COL4A5 which was previously described as pathogenic3. Mutations in COL4A5 have previously been found in individuals with Alport syndrome, a disease which is often mistaken for IgAN. We are currently working to confirm these candidate mutations via Sanger sequencing and will be screening for segregation., Atherosclerosis is a chronic inflammatory disorder that is responsible for approximately 71% of incidents of cardiovascular disease. A mathematical model of atherosclerosis has been developed, capturing the cell types and proteins involved in atheroma formation and describing the dynamics of disease progression. This is the first model of this type to be developed using open systems biology standards. We have predicted tertiary protein structures for all the proteins involved in this atherosclerosis model and all of their recorded mutations, using phase 3 sequence data obtained from the 1000 Genomes Project. By comparing the electrostatic potentials of these tertiary structures, we predict how the dynamics of atherosclerosis stratifies across population subgroups., The aim of this pilot study was to test the feasibility of carrying out a large scale study using this design to investigate whether methylation of the oxytocin receptor (OXTR) can serve as a potential biomarker for response to oxytocin administration in women during and after labour. Background Oxytocin is a nine-amino acid peptide with hormonal and neurotransmitter functions during labour and lactation. We hypothesised that a difference in methylation levels of the oxytocin receptor (OXTR) gene may impact the woman’s ability to become established in labour and her response to oxytocin administration. Method Blood samples were taken pre-birth and postnatally from 21 women and subjected to DNA methylation analysis of the OXTR gene by pyrosequencing. Methylation status of CpG sites -924 and -934 upstream from the initiation transcription site (ITS) of the OXTR gene was determined. Expression of the OXTR gene before and after birth was measured using qPCR. Global methylation levels were examined using Luminometric Methylation Assay (LUMA). Results We found both hypo and hypermethylation of OXTR promoter at CpG sites -924 and -934 in individual samples, however we observed no profound changes in overall OXTR methylation levels within the patient cohort at these CpG sites. We found a strong correlation between OXTR promoter methylation levels found in whole blood and those found in matched PMBC samples. Global methylation analysis using Luminometric Methylation Assay (LUMA) revealed no significant differences between whole blood and PMBC. Conclusions A larger sample is required to determine whether OXTR methylation status is predictive of response to oxytocin administration. Whole blood sampling is a suitable alternative for OXTR methylation analysis in a larger cohort of women undergoing labour., Background Cardiovascular disease (CVD) is the leading cause globally of morbidity and mortality. microRNAs (miRNAs) are small, non-coding RNAs which have a fundamental role in the pathology of various diseases including CVD. Circulating serum levels of miRNAs have been proposed as potentially valuable markers of heart failure, stroke, myocardial infarction and arterial hypertension, but the specific miRNAs involved and their function remains unclear. Therefore, this pilot study aims to profile miRNA expression in premature CVD patients to identify which miRNAs correlate best with hypertension. Methods The Multiplex Circulating miRNA Assay with Firefly™ Particle Technologies was used to profile 68 miRNAs on a cardiology focus panel in serum samples from 170 premature CVD patients recruited from Altnagelvin Area Hospital and screened for the C677T polymorphism in methylenetetrahydrofolate reductase, a risk factor for hypertension. Samples were collected at baseline and following intervention with riboflavin, a co-factor for MTHFR, which significantly lowers blood pressure specifically in adults with this polymorphism. Statistical analysis was used to correlate miRNA expression with blood pressure, MTHFR genotype and other relevant clinical data. Results The assay successfully measured miRNA expression in the sample set. miRNAs which expressed differentially between MTHFR genotype groups were highlighted and the functional significance of these miRNAs was assessed using bioinformatics to identify target genes involved in CVD. Conclusions The data provides further evidence that using specific miRNAs as serum markers could aid early prediction of CVD and may lead to better diagnostic modalities and therapeutic regimes., Gene-environment interactions, particularly in genes related to regulation of serotonin and neuronal function, have been implicated in the aetiology of depression. Allelic variations in the 5’ flanking transcriptional region of the serotonin transporter gene (5-HTTLPR) and higher levels of promoter DNA methylation are associated with depression. Brain derived neurotrophic factor (BDNF) plays an important role in neuronal differentiation and survival, and is also involved in regulation of serotonin. A single nucleotide polymorphism in the BDNF gene, leading to a valine to methionine substitution at codon 66 (Val66Met), and increased methylation of the BDNF promoter have also been associated with depression. The goal of this study is to determine whether length of the 5-HTTLPR, prevalence of the Val66Met polymorphism of the BDNF gene and DNA methylation in both 5-HTT and BDNF promoter regions are associated with depression in the student population. First year students provided a saliva sample for genetic analysis and completed an online mental health survey. Presence and severity of depression was determined from survey responses based on DSM-IV criteria. Length of the 5-HTTLPR was determined by PCR and gel electrophoresis and presence of the SNP at BDNF rs6265 and examined using restriction fragment length polymorphism analysis. Bisulphite-treated DNA was amplified by PCR and pyrosequencing assays used to determine methylation patterns of BDNF and SERT. Our preliminary findings suggest that genetic and epigenetic variation in the 5HTT and BDNF genes are associated with depression in the student population and may be candidate biological markers to assist in diagnosis., BACKGROUND Prostate cancer is the most common male cancer in the UK, where it kills approximately 11,000 men annually. There has been growing interest in the role played by the anaerobic bacterium Propionibacterium acnes, an important component if the skin microflora, in the aetiology of the condition via a chronic, asymptomatic infection of the prostate leading to oncogenesis. METHODS A quantitative real-time PCR (qRT-PRC) assay for retrospective detection of P. acnes in formalin-fixed paraffin embedded sections from archived prostate samples was developed. An in vitro infection model of prostate infection with P. acnes is being optimised, which should allow us to get insight into the dysregulation P. acnes infection causes in prostate epithelial cells. RESULTS A total of 81 biopsy samples, representing one or both prostate lobes, were examined from 53 patients with prostate carcinoma, versus 111 samples from 60 patients whose biopsies were histologically normal, and the assay revealed that 35% of cancerous prostate samples were positive for the presence of P. acnes, compared with only 8% of the disease-free samples (p, Oral squamous cell carcinoma (OSCC) is one of the top ten most prevalent cancers in the world. Prognosis is poor and quality of life is commonly reduced for patients who survive. OSCC is thought to progress via a premalignant stage called dysplasia. Effective treatment of dysplasia prior to malignant transformation, or the ability to more accurately predict the 10-20% of dysplasias that will progress to OSCC, is an unmet clinical need. With the aim to better understand the biology of OSCC development, and attempt to identify potential markers of early disease and therapeutic targets, we performed parallel whole exome sequencing and total RNA sequencing on 16 micro-dissected formalin-fixed paraffin embedded dysplasia and their associated OSCC. These are the largest omic analyses on matched patient samples from the oral cavity in non-HPV infected patients where all dysplasias are associated with progression to OSCC, that has been performed to date. Whole exome analysis revealed that every OSCC and adjacent associated dysplasia sample did have a common clonal ancestor, with many shared potential drivers of progression, but that there is also considerable genomic heterogeneity between associated pre-invasive and invasive disease, as seen in a previous study1. RNAseq analysis revealed differences in the immune cell signatures present at different disease stages, distinguished early events in pathogenesis from later events and identified several novel coding and non-coding candidates with potential involvement in oral dysplasia development and malignant transformation. These findings merit further investigation in a larger retrospective longitudinal study of patients with oral dysplasia., Many disorders involving tissues, which have significant energy requirements, involve mitochondrial dysfunction often due to mutations affecting the mitochondrial genome. Some such mutations can involve genes coding for subunits of complex I of the electron transport chain leading to a complex I deficiency in disorders such as Leber Hereditary Optic Neuropathy (LHON) amongst others. Mitochondrial dysfunction leads to a lack of energy production and ultimately the death of the cell. In disorders such as LHON, retinal ganglion cells (RGCs) are affected, leading to retinal dysfunction. These observations have prompted interest in exploring innovative therapeutics to modulate mitochondrial disorders involving complex I deficiency. The Farrar laboratory has explored candidate gene therapies for complex I deficiency using Ndi1, a yeast gene which is a complex I homologue. In order to test the efficacy of candidate therapies, we have developed a robust, empirical assay of mitochondrial function. Previous assays measured the level of NADH oxidation in a sample, both before and after rotenone as a measure of complex I activity. To optimally distinguish between the activity of complex I and the potential therapeutic, the assay was modified with the addition of a second inhibitor which allowed specific measurement of the therapeutic, such as Ndi1. Given that this is an in vitro assay, it enables large-scale screening of potential therapeutics and ensures only those that show strong evidence of efficacy are then tested in vivo. In combination with other quantitative assays such as Reactive Oxygen Species (ROS) generation this allows detailed evaluation of the health of mitochondria within a sample., Schizophrenia is an adult-onset mental illness with that impacts cognitive function. The largest GWAS has revealed 108 loci associated with schizophrenia risk but how variation affects genes and impacts brain function to increase risk is largely unknown. The centrosome is the microtubule organising centre of the cell and seeds the growth of the primary cilium. The disproportionate number of brain disorders associated with centrosomal genes suggests the organelle underlies normal brain and cognitive development. Schizophrenia is neurodevelopmental and cognitive deficits are a core element of the disorder. We hypothesise that some of the newly identified risk genes for schizophrenia will function in the centrosome and variants in these genes will be associated with cognitive deficits. Cross-referencing genes with centrosomal functions with genes from schizophrenia GWAS, identified six candidate genes; SDCCAG8, MAD1L1, GIGYF2, MPHOSPH9, PRKD1 and MAPK3. The effect of risk SNPs on cognition was examined using an Irish dataset of psychosis cases and controls (n=1,236) using linear regression. Among the associations identified, the SDCCAG8 risk SNP was shown to affect attribution style, a measure of social cognition (P=0.001). The MAD1L1 risk SNP was associated with poorer performance on episodic memory tasks (P=0.003). A suitable replication dataset was not available for social cognition measures. We attempted replication for episodic memory results in UK and German samples but results were non-significant. Overall, we have identified a number of schizophrenia risk genes that function in the centrosome but further larger datasets are required to establish a role for these genes in cognition., Epigenetic mechanisms are an important heritable and dynamic means of regulating various genomic functions, including gene expression to orchestrate brain development. These processes when perturbed are thought to contribute to schizophrenia (SZ). A core feature of SZ is cognitive dysfunction. GWAS have identified 108 genomic loci associated with SZ risk, containing 350 genes. My aim was to identify genes that have epigenetic functions which map to loci associated with SZ, and to test the associated SNPs for association with cognitive deficits. Risk SNPs in 8 genes: BCL11B, CHD7, EP300, EPC2, GATAD2A, KDM3B, RERE and SATB2 were analysed using an Irish dataset of psychosis cases and controls (n=1235) who had completed tests across 5 cognitive domains. Five of the eight variants had significant associations with at least one cognitive task. Strongest associations were for CHD7 (rs6984242) for IQ (p=0.001) and episodic memory (p=0.007). These results did not replicate in independent samples. We link rs6984242 to CHD7 via a long range expression quantitative trait loci (eQTL) and CHD7 has not been previously reported as a candidate risk gene for SZ. To further explore its novel association with SZ, we identified a set of 45 interacting genes and used SNPs across these genes to develop a polygenic risk score for SZ, independent of CHD7 itself. This score was tested for association with cognitive function. Significant associations(p, The relevance of nutrition and other environmental influences on epigenetic modifications including DNA methylation is a topic of considerable interest. Folate One Carbon Metabolism (FOCM) is the principal supplier of the methyl groups required for DNA methylation, giving folate status a strong biological plausibility of having an impact on an individual’s and an offspring’s DNA methylation profile at both the mitotic and meiotic level. We sought to identify DNA methylation sites in the human genome that are sensitive to folate status i.e., Folate-sensitive Differentially Methylated Regions (FS-DMR) using a folic acid intervention trial in pregnant women known as FASSTT (Folic Acid Supplementation in the Second and Third Trimesters). To minimize the amount of DNA methylation ‘noise’ due to non-folate related factors such as other environmental stimuli and individual genetic variation, we compared the DNA methylation profile of the same individual pre- and post- intervention to identify putative FS-DMR. We selected six healthy pregnant women, three from the folic acid intervention arm and three from the placebo arm of the trial. We performed MeDIP (Methylated DNA Immunoprecipitation) on all 12 samples and hybridized to a Roche Nimblegen Delux 2.1M promoter array. While we observed DNA methylation changes pre- and post- folic acid intervention in each individual, the actual DNA methylation sites were not consistent across all three individuals. Of course, it is possible that a more in-depth Next Generation Sequencing approach might yield our elusive FS-DMRs. However, the published literature to date does not appear to support such a promise., The loss of retinal ganglion cells (RGCs) is a hallmark of a number of retinopathies. There are a number of gene therapies being developed that have shown efficacy in preserving RGCs when administered using an AAV vector. Localising expression of any therapeutic to the target cell type (ganglion cell layer, GCL) would represent a significant optimisation of the approach. The packaging capacity of AAV (4.7kb) imposes a limit on the size of promoters and genes relevant for AAV-mediated gene delivery. Few GCL-specific promoter sequences have been defined of a size suitable for use in AAV-guided gene expression. Exploring this, a panel of genes was chosen with GCL-limited expression profiles. A pipeline program was developed that analysed regions upstream of these genes for sequence conservation across placental mammals (as a proxy for putative promoter function), weighted by enriched GCL expression levels. Adopting this strategy, ganglion cell promoter 1 (GCP1), demonstrating the key features outlined above, was identified. To test its function, GCP1 (2.2kb in size) was engineered into an AAV2 virus expressing EGFP. Here we demonstrate the effectiveness of GCP1 in localising EGFP expression to the GCL when administered via intravitreal injection. Furthermore, absence of EGFP expression was demonstrated when targeted towards photoreceptors via subretinal injection, verifying GCP1 tissue-specificity. Expression of AAV2.GCP1-EGFP was compared to expression from a non-specific promoter construct, AAV2.CMV-EGFP. GCP1-EGFP was shown to provide equivalent expression to CMV-EGFP in the GCL. GCP1 thus offers a tissue-specific promoter option, suitable for deployment within AAV vectors without compromising functionality., Purpose Hypoxia is a common hallmark of the tumour microenvironment. Recently we have shown the anti-androgen bicalutamide induces profound hypoxia in prostate tumours in vivo. This resulted in the promotion of epithelial to mesenchymal transition. Here we target tumour hypoxia using a novel unidirectional hypoxia-activated prodrug OCT1002 to enhance the anti-tumour effect of bicalutamide. Experimental Design The effect of OCT1002 treatment on LNCaP-luc cells was measured in normoxia and hypoxia in vitro. In vivo, tumour growth and lung metastases were measured in mice treated with bicalutamide, OCT1002 or a combination. Dorsal skin fold chambers were used to image tumour vasculature in vivo. Longitudinal genetic changes in tumours were analysed using PCR. Results Reduction of OCT1002 to its active form (OCT1001) decreased LNCaP-luc cell viability. In LNCaP-luc spheroids, OCT1002 caused increased apoptosis and decreased clonogenicity. In vivo, treatment with OCT1002 alone or with bicalutamide, showed significantly greater tumour growth control and reduced lung metastases compared to controls. Re-establishment of the tumour vasculature following bicalutamide-induced vascular collapse is inhibited by OCT1002. Significantly, the up-regulation of RUNX2 and its targets caused by bicalutamide alone were also blocked by OCT1002. Conclusions OCT1002 selectively targets hypoxic tumour cells and enhances the anti-tumour efficacy of bicalutamide. Furthermore, bicalutamide causes changing genetic profiles during treatment, with development of a more malignant genotype; OCT1002 can block this effect. This study indicates that more attention should be attached to understanding genetic changes that may occur during treatment. Early targeting of hypoxic cells with OCT1002 can provide a means of inhibiting prostate tumour growth and malignant progression., Background In prostate cancer (PCa), abnormal expression of several microRNAs (miRNAs) has been previously reported. Increasing evidence shows that aberrant epigenetic regulation is a contributing factor to their altered expression in cancer. In this study we investigate whether expression of miR-200c and miR-141 in PCa is related to the DNA methylation status of their promoter. Methods PCR analysis of miR-200c and miR-141, and CpG methylation analysis of their common promoter, was performed in PCa cell-lines and in FFPE prostate biopsy specimens. The functionality of miR-200c and miR-141 expression in prostate cancer cells was assessed by a series of in vitro bioassays. Results miR-200c and miR-141 expression correlates inversely with the methylation status of the miR-200c/miR-141 promoter in PCa cells. In PC3 cells, miR-200c and miR-141 expression is elevated by treatment with the demethylating agents suggesting their expression is linked to methylation. Expression of miR-200c and miR-141 in prostate biopsy tissue was inversely correlated with methylation in CpG sites closest to the miR-200c/miR-141 loci. Over-expression of miR-200c in PC3 cells inhibited growth and clonogenic potential, as well as inducing apoptosis. Expression of the genes DNMT3A and TET1/TET3 were down-regulated by miR-200c and miR-141 respectively. Finally, treatment with the soy isoflavone genistein caused demethylation of the promoter CpG sites closest to the miR-200c/miR-141 loci resulting in increased miR-200c expression. Conclusions Our findings provide evidence that miR-200c and miR-141 are under epigenetic regulation in PCa cells. Profiling their expression and methylation status may have potential in the improved diagnosis and prognosis of PCa., Increasingly accurate surveys of human health throughout the life course has led experts to propose that stresses on the child while still in the mother’s womb can affect the individual’s health much later in life. Such long-term effects on health are thought to be mediated by a semi-permanent trace on the genes of the affected person called an epigenetic mark. Epigenetic mechanisms, such as DNA methylation, are dynamic during pregnancy whereby epigenetic marks are seeded which persist throughout the lifetime of the developing child. It has been suggested that these patterns may be altered by the mother’s diet, particularly folate – a key component in the DNA methylation cycle. Currently, mothers are universally recommended to supplement their diet with 400μg folic acid/day as a preventative measure against neural tube defects in the offspring prior to and during the first trimester. However, there remains no clinical recommendation as to whether mothers should continue supplementation during the final two trimesters and the potentially heritable effects on DNA methylation. Observational studies have suggested that folate-rich maternal diets are associated with changes in DNA methylation of the child during this period of gestation. We present here the results of a randomised control trial (FASSTT study) examining the effects of folic acid supplementation in late gestation (week 12 onwards) on DNA methylation of several gene classes in offspring cord blood samples. We report small but significant sex-specific differences between the two intervention groups. These preliminary results indicate that folic acid supplementation throughout pregnancy may exert significant effects on cord blood DNA methylation., Introduction New-onset diabetes after transplantation (NODAT) is a common complication of kidney transplantation which increases risk of subsequent graft failure, cardiovascular complications and death. NODAT is defined as the new requirement for oral hypoglycaemic agents or insulin as a result of hyperglycaemia after renal transplant. The first genome wide association study (GWAS) for NODAT was published by our group in 2014; seven of the eight top-ranked, common SNPs are implicated in β-cell apoptosis. Methods To further understand the genetic architecture of the NODAT phenotype we used whole exome sequencing for 134renal transplant recipients from a Northern Ireland renal transplant cohort. We sequenced 53 individuals with NODAT (cases)and 81 transplant recipients without NODAT (controls). Library preparation was performed using the Ion TargetSeq™ Exome Kit with samples sequenced on an Ion Torrent Proton sequencer. TheIon OneTouch 2 for emulsion PCR and Ion Enrichment System were used. Association analysis was performed using PLINK Version 1.9 to identify variants associated with NODAT (with age and weight at transplant included in the regression model). Results Following appropriate quality control, initial analysis identified 6 variants nominally associated with NODAT (Ptrend, The Irish Traveller community has a high incidence of autosomal recessive (AR) disorders due to consanguinity. The Division of Molecular Genetics at the DCG offers genetic testing, primarily to members of this community, for five specific pathogenic mutations found in five AR disorders. The pathogenic mutations are detected by bi-directional Sanger sequencing and the service includes: Gene Disorder/ Disease Phenotype LARS (leucyl-tRNA synthetase) Infantile Liver Failure Syndrome 1 (ILFS1) Infantile hepatopathy with failure to thrive (FTT) and developmental delay. MCM4 (minichromosome maintenance 4) Natural Killer Cell & Glucocorticoid Deficiency with DNA Repair Defect (NKGCD) FTT, adrenocorticotropin hormone (ACTH) resistance, familial glucocorticoid deficiency (FGD), mosaic Fanconi anaemia and recurrent infections due to NK cell deficiency. STRA6 (stimulated by retinoic acid 6 gene) Autosomal recessive isolated colobomatous microanopthalmia (MCOPS9) Microphthalmia, anophthalmia, coloboma.Specific STRA6 mutation can also cause the Matthew-Wood syndrome [anophthalmia/ severe microphthalmia, with pulmonary hypoplasia/ aplasia] LEPRE1 (Leucine-and proline-enriched proteoglycan 1)syn. PH31(prolyl-3-hydroxylase-1) Type VIII Osteogenesis Imperfecta, Variable phenoptype of bone fragility, susceptibility to fracture, short stature, bowing of the long bones and can be perinatally lethal. ATP8B1 (ATPase, Class I, Type 8B, Member1) Progressive Familial Intrahepatic Cholestasis type 1 (PFIC1) syn. Byler disease Hepatic and systemic accumulation of bile acids, hepatic fibrosis, end-stage liver disease and growth retardation. This study will detail (1) the service offered to users, (2) an audit of the test requests received over the last two years, (3) the challenges encountered in offering this unique service and (4) some interesting family pedigrees., Background Hypoxia in prostate tumours has been linked with promotion of disease progression and metastasis. miR-210 is a microRNA which is apparently affected by hypoxia, but this relationship has not been extensively studied in a prostate cancer setting. Therefore, in this study, we investigate the link between hypoxia and miR-210 in prostate cancer cells. Methods We have used 2D and 3D cell prostate cell models of hypoxia to investigate the functionality of miR-210. Expression levels of miR-210 have been measured by qPCR and functional bioassays used to examine its effect on prostate cell behaviour. Target genes have been identified and bioinformatic analysis has been employed to investigate a clinical significance for miR-210 in prostate cancer. Results miR-210 is induced by hypoxia in prostate cancer cell-lines. Over-expression of miR-210 impacts upon target genes, including SP1 and TPD52, which in turns affects cell proliferation. Data-mining of online repositories of clinical data and bioinformatic analysis of miR-210 cellular networks reveal that miR-210 plays a key role in a number of important cell processes, the dysregulation of which can lead to development of prostate cancer. Conclusions We propose that miR-210 could be an important microRNA in the pathogenesis of prostate cancer and has potential as a biomarker in this disease.

Aims The Irish DNA Atlas is a DNA collection being assembled with the aim of describing the fine-scale population structure in Ireland. Understanding such structure can inform on optimal design of clinical genetic studies as well as the history of the Irish population. We will present an overview of and the preliminary findings from the study. Methods We are recruiting individuals with all eight greatgrandparents born in Ireland, within 30 kilometres of each other. Participants are asked to complete a detailed birth-brief, which records place and date of birth of three generations of ancestors. We also collect some basic health-related details. DNA is extracted from a saliva sample. We have genotyped using an Illumina OmniExpressdense SNP genotyping platform. We present a number of analyses designed to visualise genetic structure, including; Principle Component, ADMIXTURE, and Runs of Homozygosity analysis. Results To date we have recruited 162 participants. The mean great-grandparental area is 32 kilometres, with an average greatgrandparental date of birth of 1850. Therefore the individuals in the Atlas provide insight to the genetic landscape of Ireland before significant movement of people from the 20th century onwards. An analysis of dense genotyping data from 142participants shows that the Atlas participants cluster closely with British individuals in a Europe wide PCA, but present different ancestral population components when compared with British, and other European populations. Irish individuals also present slightly higher levels of homozygosity relative to mainland European levels. PCA targeted at specific areas of interest within Ireland also hint at fine-scale substructure. Conclusion Ireland shows typical features of a homogenous population, well suited to the study of rare variation in disease risk., Background Progress in diagnostic and therapeutic strategies in medicine is dependent upon high-quality biomedical research. Translation of research findings into the clinic relies on patient participation in innovative clinical trials. We investigated attitudes to genetic research in Ireland, in particular with respect to commercial and financial implications. Methods A multi-centre cross-sectional survey study was performed. Consecutive patients attending four out-patient clinics were asked to complete paper-based questionnaires. An electronic version of the same questionnaire was created on Survey Monkey with a link made public on a social media website for a period of 24 hours. Data was analysed using SPSS. Results 351 questionnaires were completed (99 paper, 252 electronic). The majority of respondents were female (n = 288, 82%), and highly educated, with 244 (70%) attending college/university. Most participants supported genetic research (267, 76%), more frequently for common diseases (274, 78%) than rare disorders (204, 58%, p < 0.001, x2). 103 (29%) had participated in scientific research, and 57(16%) had donated material to a bio-bank. The majority (n = 213, 61%) would not support research with potential financial/commercial gain. 106(30%) would decline to participate in research if researchers would benefit financially, compared to 49(14%) if the research was supported by a pharmaceutical company, (p < 0.001, x2). Respondents would provide buccal samples (258, 74%) more readily than tissue (225, 64%) or blood (222, 63%). Conclusion A high level of support for genetic research exists among the Irish population, but active participation is dependent upon a number of factors, notably, type of biological material required, frequency of the disease in question, and commercial interest of the researchers., Introduction Although the etiology of schizophrenia (SZ) is largely unknown, it is increasingly clear that genetic and environmental interactions contribute to cognitive deficits associated with this disorder. Recent Genome wide association studies (GWAS) have indicated a link between SZ and immune dysregulation, especially genetic mutations related to the major histocompatibility complex (MHC). Cognitive deficits are core features of Schizophrenia and related disorders, which relate to genetic risk. This study aims to explore the relationship between MHC risk variants for SZ and cognitive deficits, while also relating findings to brain activity. Methods To test if MHC risk variants impair cognition, ANCOVA analysis is performed on genetics data previously collected in a GWAS. Cognition measures are compared in groups with and without MHC genetic risk, in a population of SZ sufferers and healthy controls. Functional MRI imaging will also be performed to test if genetic risk relates to altered neural activity. Results Preliminary analyses suggest that MHC risk variants contribute to impairments in cognition in domains of social cognition, IQ and attention. Further analysis will be performed to test for environmental mediators of this relationship, looking at cannabis use and urbanicity. BOLD fMRI will also be used to test for a relationship between MHC risk and altered neural activity, using MATLAB SPM. Conclusions The MHC genetic variant may serve as a significant risk marker for schizophrenia, and further elucidate etiology of this neurodevelopmental disorder. Future studies on neurobiology of social cognition, and greater knowledge of genetic risk may establish targets for interventions., Aim To create a bioluminescence mouse model which expresses firefly luciferase in the corneal epithelium to assess gene editing and gene silencing for the cornea. Methods A gene targeting vector was generated where the Krt12 coding sequence in and the splice donor site of exon 1 were replaced with a transgene cassette containing a luc2-Multiple Targeting Cassette (MTC) gene fusion. The vector was transfected by electroporation into the Taconic Artemis C57BL/6N Tac ES cell line. Homologous recombinant clones were isolated and validated, and the mice bred with luc2-positive/ PuroR-negative offspring used for colony establishment. To visualise the expression of luc2 within the corneal epithelium, luciferin substrate diluted in viscotears was applied to the front of the eye and then luciferase expression was imaged and assessed using a Xenogen IVIS Lumina Imager and LivingImage 3.2 software. Intrastromal injection of siGlo siRNA was used to determine the localisation of siRNA within the corneal epithelium and then the established mouse model was treated with either native or Accell “self-delivery” siRNA. Results The Accell “self-delivery” siRNA induced potent sustained allele specific silencing for 7 days, while native versions of siRNA resulted in significant knock-down for 1 day only (p < 0.05). We have created and validated a bioluminescence mouse model and have utilised it to assess siRNA in vivo. This mouse model coupled with the Lumina imager will allow us to assess topical delivery of gene therapies to the ocular surface allowing validation for future translation to clinical use., Background Methylation of DNA sequences at promoters, CpG islands and other elements plays a vital role in regulating gene activity. In human, loss of methylation is known to play a causative role in imprinting disorders and in inappropriate germline gene expression in cancers. While in mouse, loss of function mutants have given great insight into the targets of methylation, functional studies in human have been largely limited to cancer cells and more recently stem cells, not normal adult cells. Methods Stable knockdowns of the maintenance methyltransferase DNMT1 were generated in normosomic hTERT-immortalised adult fibroblasts. Genome-wide methylation levels were assayed using the Illumina 450K bead array. Results were analysed using RnBeads and Galaxy. Locusspecific methylation was verified using pyrosequencing and clonal analysis. Validation was achieved using transient siRNA. Results Loss of function was poorly tolerated and all clonally-expanded cell lines had spontaneously restored DNMT1 levels by silencing of the shRNA. Evidence for a genome-wide methylation erasure event followed by a wave of remethylation could be clearly traced. Gene bodies and the shores of CpG islands showed the clearest loss of methylation overall. While most CpG islands are normally unmethylated and so unaffected, both imprints and germline genes fall into the rarer category of normally methylated islands: of these two, lasting loss of methylation was much more common among imprints than germline genes. Conclusions 1: transient loss of methylation is poorly tolerated; 2: a robust mechanism for remethylation exists even in adult cells; 3: aberrant remethylation is frequent on recovery and 4: Imprints are particularly sensitive., Background Dihydrofolate reductase (DHFR) is essential for the conversion of folic acid to active folate needed for one-carbon metabolism. Common genetic variation within DHFR is restricted to the noncoding regions and previous studies have focused on a 19 bp deletion/insertion polymorphism (rs70991108) within intron 1. Reports of an association between this polymorphism and blood folate biomarker concentrations are conflicting. Objective We aimed to evaluate whether the DHFR 19bp deletion/ insertion polymorphism affects circulating folate biomarkers in the largest cohort to address this question to date. Methods Young healthy Irish individuals (n= 2,507) between 19 to 36 years old were recruited between February 2003 and 2004. Folic acid intake from supplements and fortified foods was assessed using a customized food intake questionnaire. Concentrations of serum folate and vitamin B-12, red blood cell (RBC) folate and plasma total homocysteine (tHcy) concentration were measured. Data were analysed using linear regression models. Results Folic acid intake was positively associated with serum (P 326μg folic acid/day; P = 0.96). A non-significant trend towards lower RBC folate by genotype (P = 0.09) was observed in the lowest folic acid intake quintile (0 – 51 μg/day). Conclusion In this cohort of young healthy individuals the DHFR 19bp deletion allele does not significantly affect circulating folate status, irrespective of folic acid intake. Our data rule out a strong functional effect of this polymorphism on blood folate concentrations.