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Lynch syndrome (hereditary non-polyposis colorectal cancer; HNPCC) is an autosomal dominant cancer predisposition syndrome with high penetrance. It is caused by heterozygous germline mutations in one of the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2. Carriers are at high-risk for developing colorectal carcinomas, as well as various extracolonic malignancies. This case report describes a 15 year-old male with a confirmed germline mutation of MSH2 and early onset anaplastic oligodendroglioma. The patient's tumor showed loss of expression of MSH2 and MSH6 proteins with normal microsatellite stability. The immunohistochemical staining pattern provided strong evidence to support the inclusion of anaplastic oligodendroglioma as part of the spectrum of tumors found in Lynch syndrome.

Direct-to-consumer genetic testing (DTC-GT) allows individuals to obtain genetic tests directly from companies without necessarily involving health professionals. This study explores genetic health professionals' opinions of health-related DTC-GT and the reported frequency of individuals presenting to clinical genetics services after undertaking testing. Genetic counsellors and clinical geneticists, members of the Human Genetics Society of Australasia, completed an online survey in mid 2011. The 130 genetic counsellors (estimated response fraction=43%) and 38 clinical geneticists (estimated response fraction=46%) had mixed opinions regarding DTC-GT, with only 7% confident in accurately interpreting and explaining DTC-GT results. Nineteen respondents (11%) reported one or more client(s) referred to them after undertaking DTC-GT. Descriptions of 25 clients were extracted from responses, and respondents reported that all clients were concerned for the health of either themselves or family members. Most clients presented to genetic clinics specifically as a result of their DTC-GT (96%) and were self or GP referred (92%). Respondents perceived that their clients typically undertook DTC-GT because they wanted to identify monogenic conditions, including carrier testing and/or know their susceptibility or predisposition for complex conditions (88%). The majority of clients needed help interpreting DTC-GT results (80%), however in general were not questioning the validity of their DTC-GT results (92%) nor seeking further genetic testing (84%). Currently, DTC-GT is not a major reason for referral to clinical genetics services in Australia and New Zealand and the majority of genetic health professionals lack confidence in being able to accurately interpret and explain DTC-GT results.

Background Chromosome 15q24 microdeletion syndrome is a rare genomic disorder characterised by intellectual disability, growth retardation, unusual facial morphology and other anomalies. To date, 20 patients have been reported; 18 have had detailed breakpoint analysis. Aim To further delineate the features of the 15q24 microdeletion syndrome, the clinical and molecular characterisation of fifteen patients with deletions in the 15q24 region was performed, nearly doubling the number of reported patients. Methods Breakpoints were characterised using a custom, high-density array comparative hybridisation platform, and detailed phenotype information was collected for each patient. Results Nine distinct deletions with different breakpoints ranging in size from 266 kb to 3.75 Mb were identified. The majority of breakpoints lie within segmental duplication (SD) blocks. Low sequence identity and large intervals of unique sequence between SD blocks likely contribute to the rarity of 15q24 deletions, which occur 8–10 times less frequently than 1q21 or 15q13 microdeletions in our series. Two small, atypical deletions were identified within the region that help delineate the critical region for the core phenotype in the 15q24 microdeletion syndrome. Conclusion The molecular characterisation of these patients suggests that the core cognitive features of the 15q24 microdeletion syndrome, including developmental delays and severe speech problems, are largely due to deletion of genes in a 1.1–Mb critical region. However, genes just distal to the critical region also play an important role in cognition and in the development of characteristic facial features associated with 15q24 deletions. Clearly, deletions in the 15q24 region are variable in size and extent. Knowledge of the breakpoints and size of deletion combined with the natural history and medical problems of our patients provide insights that will inform management guidelines. Based on common phenotypic features, all patients with 15q24 microdeletions should receive a thorough neurodevelopmental evaluation, physical, occupational and speech therapies, and regular audiologic and ophthalmologic screening.

Background Several recent studies have demonstrated the use of single nucleotide polymorphism (SNP) arrays for the investigation of intellectual disability, developmental delay, autism or congenital abnormalities. In addition to LogR ‘copy number’ data, these arrays provide SNP genotyping data for gene level autozygosity mapping, estimating low levels of mosaicism, assessing long continuous stretches of homozygosity (LCSH), detection of uniparental disomy, and ‘autozygous’ regions. However, there remains little specific information on the clinical utility of this genotyping data. Methods Molecular karyotyping, using SNP array, was performed on 5000 clinical samples. Results Clinically significant ‘LogR neutral’ genotyping abnormalities were detected in 0.5% of cases. Among these were a single case of chimerism, 12 cases with low level chromosome mosaicism, and 11 cases with an LCSH associated with uniparental disomy. In addition, the genotyping data revealed several LCSH associated with clinically relevant ‘recessive type’ genetic defects. Conclusions These results demonstrate the utility of SNP genotyping data for detection of clinically significant abnormalities, including chimerism/mosaicism and recessive Mendelian disorders associated with autozygosity. The incidence of clinically significant low level mosaicism inferred from these cases suggests that this has hitherto been underestimated and chromosome mosaicism frequently occurs in the absence of indicative clinical features. The growing appreciation among clinicians and demand for SNP genotyping data poses significant challenges for the interpretation of LCSH, especially where there is no detailed phenotypic description to direct laboratory analysis. Finally, reporting of unexpected or hidden consanguinity revealed by SNP array analysis raises potential ethical and legal issues.

Microarray analysis has provided significant advances in the diagnosis of conditions resulting from submicroscopic chromosome abnormalities. It has been recommended that array testing should be a "first tier" test in the evaluation of individuals with intellectual disability, developmental delay, congenital anomalies, and autism. The availability of arrays with increasingly high probe coverage and resolution has increased the detection of decreasingly small copy number changes (CNCs) down to the intragenic or even exon level. Importantly, arrays that genotype SNPs also detect extended regions of homozygosity. We describe 14 examples of single gene disorders caused by intragenic changes from a consecutive set of 6,500 tests using high-resolution SNP microarrays. These cases illustrate the increased scope of cytogenetic testing beyond dominant chromosome rearrangements that typically contain many genes. Nine of the cases confirmed the clinical diagnosis, that is, followed a "phenotype to genotype" approach. Five were diagnosed by the laboratory analysis in the absence of a specific clinical diagnosis, that is, followed a "genotype to phenotype" approach. Two were clinically significant, incidental findings. The importance of astute clinical assessment and laboratory-clinician consultation is emphasized to optimize the value of microarrays in the diagnosis of disorders caused by single gene copy number and sequence mutations.

The Fragile X syndrome is caused by a CGG repeat expansion >200 in the promoter of the Fragile X mental retardation 1 (FMR1) gene termed full mutation (FM). These alleles are silenced through methylation of the FMR1 promoter, leading to deficit of the FMR1 protein (FMRP), and neurodevelopmental changes. However, occasional FM individuals have a complete lack of methylation, and those typically have only minor deficit of FMRP levels compared with normal controls and their intelligence may be in the normal range. FM alleles are generated through expansion of the CGG repeat from the premutation (PM) range of 55-200 repeats, linked to the late onset Fragile X-associated tremor/ataxia syndrome (FXTAS). This disorder has been attributed to a 'toxicity' of the FMR1 mRNA, which is significantly elevated in male carriers of PM alleles and of unmethylated FM alleles. This is the first report of a 65-year-old male with an unmethylated FM allele and history of alcohol abuse, who developed symptoms of FXTAS. We postulate that, although the elevation of FMR1 transcripts associated with unmethylated FM alleles have a potential to cause FXTAS, in some cases this disorder may occur through an additional effect of exposure to neurotoxicants including alcohol.

Hypertrophic cardiomyopathy (HCM) is a disease characterised by hypertrophy of the left ventricle of the heart. HCM has a prevalence of ~1 in 500 individuals and is the leading cause of sudden cardiac death among young individuals. Over 20 HCM genes have been identified but at least 20% of cases remain of unknown aetiology. An extended family presented to the Victorian Clinical Genetics Service with a syndromic form of HCM. Copy number analysis and linkage studies were performed using data from high density SNP-array analysis. A single linkage region was identified and no CNVs of interest were detected. Whole exome sequencing identified a homozygous truncating variant. To determine the potential contribution of the gene to HCM, we sequenced the gene in a cohort of HCM patients. We did not identify any predicted pathogenic variants. To investigate the function of the gene we have characterised the expression and splicing patterns in human and mouse tissues. Immunocytochemical studies demonstrated predominant localisation to the extracellular matrix. In conclusion:, we have identified a novel gene for HCM. Further characterisation of this protein will lead to increased understanding of the molecular basis of cardiomyopathy and result in improved clinical outcomes for affected individuals and families.

Familial digital arthropathy-brachydactyly (FDAB) is a dominantly inherited condition that is characterized by aggressive osteoarthropathy of the fingers and toes and consequent shortening of the middle and distal phalanges. Here we show in three unrelated families that FDAB is caused by mutations encoding p.Gly270Val, p.Arg271Pro and p.Phe273Leu substitutions in the intracellular ankyrin-repeat domain of the cation channel TRPV4. Functional testing of mutant TRPV4 in HEK-293 cells showed that the mutant proteins have poor cell-surface localization. Calcium influx in response to the synthetic TRPV4 agonists GSK1016790A and 4αPDD was significantly reduced, and mutant channels did not respond to hypotonic stress. Others have shown that gain-of-function TRPV4 mutations cause skeletal dysplasias and peripheral neuropathies. Our data indicate that TRPV4 mutations that reduce channel activity cause a third phenotype, inherited osteoarthropathy, and show the importance of TRPV4 activity in articular cartilage homeostasis. Our data raise the possibility that TRPV4 may also have a role in age- or injury-related osteoarthritis.

Objectives To map prenatal screening and diagnostic testing pathways in Victorian pregnant women during 2003 to 2004; measure the impact of prenatal diagnostic testing uptake on the effectiveness of prenatal screening for Down syndrome; and assess factors influencing uptake of diagnostic testing following screening. Methods State-wide data collections of prenatal screening and diagnostic tests were linked to all Victorian births and pregnancy terminations for birth defects. Results Overall, 52% of women had a prenatal test (65 692/126 305); screening (44.9%), diagnostic testing (3.9%), or both (3.2%). Uptake of diagnostic testing was 71.4% (2390/3349) after an increased risk screen result, and 2.5% (1381/54 286) after a low risk result. Variation in uptake of diagnostic testing reduced the effectiveness of the screening program by 11.2%: from 87.4% (sensitivity − 125/143) to 76.2% (prenatal diagnoses of Down syndrome − 109/143). In both the increased and low risk groups, uptake was influenced by absolute numerical risk, as well as by the change in numerical risk from a priori risk. Conclusions This comprehensive follow-up demonstrates clearly that numerical risk is being used to aid in decision making about confirmatory diagnostic testing. Collectively, these fundamental individual decisions will impact on the overall effectiveness of screening programmes for Down syndrome. Copyright © 2010 John Wiley & Sons, Ltd.

Contains fulltext : 88561.pdf (Publisher’s version ) (Closed access) BACKGROUND: Chromosome 17p13.3 contains extensive repetitive sequences and is a recognised region of genomic instability. Haploinsufficiency of PAFAH1B1 (encoding LIS1) causes either isolated lissencephaly sequence or Miller-Dieker syndrome, depending on the size of the deletion. More recently, both microdeletions and microduplications mapping to the Miller-Dieker syndrome telomeric critical region have been identified and associated with distinct but overlapping phenotypes. METHODS: Genome-wide microarray screening was performed on 7678 patients referred with unexplained learning difficulties and/or autism, with or without other congenital abnormalities. Eight and five unrelated individuals, respectively, were identified with microdeletions and microduplications in 17p13.3. RESULTS: Comparisons with six previously reported microdeletion cases identified a 258 kb critical region, encompassing six genes including CRK (encoding Crk) and YWHAE (encoding 14-3-3epsilon). Clinical features included growth retardation, facial dysmorphism and developmental delay. Notably, one individual with only subtle facial features and an interstitial deletion involving CRK but not YWHAE suggested that a genomic region spanning 109 kb, encompassing two genes (TUSC5 and YWHAE), is responsible for the main facial dysmorphism phenotype. Only the microduplication phenotype included autism. The microduplication minimal region of overlap for the new and previously reported cases spans 72 kb encompassing a single gene, YWHAE. These genomic rearrangements were not associated with low-copy repeats and are probably due to diverse molecular mechanisms. CONCLUSIONS: The authors further characterise the 17p13.3 microdeletion and microduplication phenotypic spectrum and describe a smaller critical genomic region allowing identification of candidate genes for the distinctive facial dysmorphism (microdeletions) and autism (microduplications) manifestations. 01 mei 2010

To determine whether adverse perinatal outcomes are increased in subfertile women.Cohort study.Two tertiary assisted reproductive technologies (ART) centers; Victorian births register.Records of women who registered with the clinics (1991-2000), but did not have an infant using ART, were linked to the birth register (1991-2004) to identify singleton non-ART births within 5 years of registration (N = 2171). Controls, matched by maternal age and year of infant's birth, were selected randomly from birth records (N = 4363).None.Adverse obstetric and perinatal outcomes.After adjusting for confounders, compared with controls, subfertile women had increased odds of hypertension or preeclampsia (adjusted odds ratio [OR] 1.29, 1.02-1.61), antepartum hemorrhage (adjusted OR 1.41, 1.05-1.89), perinatal death (adjusted OR 2.19, 1.10-4.36), low birth weight (adjusted OR 1.44, 1.11-1.85), preterm birth37 weeks (adjusted OR 1.32, 1.05-1.67) or31 weeks (adjusted OR 2.37, 1.35-4.13), and cesarean delivery (adjusted OR 1.56, 1.37-1.77). There was weak evidence for increased birth defects (adjusted OR 1.30, 0.98-1.72) and gestational diabetes (adjusted OR 1.25, 0.96-1.63). No increased risk was found for prelabor rupture of membranes, small for gestational age, or postpartum hemorrhage.Subfertile women with singleton births are at increased risk of several adverse outcomes. These risks should be considered during their antenatal care and when analyzing adverse effects of ART.

background: The reasons for increased birth defect prevalence following in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are largely unknown. Classification of birth defects by pathology rather than organ system, and examination of the role of embryo freezing and thawing may provide clues to the mechanisms involved. This study aimed to investigate these two factors. method: Data on 6946 IVF or ICSI singleton pregnancies were linked to perinatal outcomes obtained from population-based data sets on births and birth defects occurring between 1991 and 2004 in Victoria, Australia. These were compared with 20 838 outcomes for singleton births in the same population, conceived without IVF or ICSI. Birth defects were classified according to pathogenesis. results: Overall, birth defects were increased after IVF or ICSI [adjusted odds ratio (OR) 1.36; 95% CI: 1.19– 1.55] relative to controls. There was no strong evidence of risk differences between IVF and ICSI or between fresh and thawed embryo transfer. However, a specific group, blastogenesis birth defects, were markedly increased [adjusted OR 2.80, 95% CI: 1.63 –4.81], with the increase relative to the controls being significant for fresh embryo transfer (adjusted OR 3.65; 95% CI: 2.02 –6.59) but not for thawed embryo transfer (adjusted OR 1.60; 95% CI: 0.69 –3.69). conclusion: Our findings suggest that there is a specific risk of blastogenesis birth defects arising very early in pregnancy after IVF or ICSI and that this risk may be lower with use of frozen-thawed embryo transfer.

Extra structurally abnormal chromosomes (ESACs) derived from the X chromosome are rare. We report a non-mosaic ESAC derived from the X chromosome in a 3-year-old female who presented with early hypotonia, developmental delay, hypertelorism, low set ears, and small hands and feet. The breakpoints of the ESAC were mapped by SNP microarray to Xp11.1-p11.22, a region encompassing 7.17 Mb and containing 110 known or putative genes and excluding the X-inactivation center. A review of other reported patients with karyotypes that cause functional disomy of proximal Xp allows delineation of a common phenotype comprising early hypotonia, cognitive impairment, hypertelorism, myopia, small hands and feet and abnormal external ears.

Microdeletions at 14q12 that include FOXG1, or loss of function mutations in FOXG1, are associated with the congenital variant of Rett syndrome. By SNP microarray analysis we identified a corresponding microduplication at 14q12 in a nine year old girl with symptomatic generalised epilepsy, severe intellectual impairment, and minor dysmorphisms, but without microcephaly. The 14q12 microduplication comprised 4.45 Mb of DNA and included FOXG1. This is the first report of duplication involving FOXG1 and suggests a dosage sensitive role for FOXG1 in brain development.

First trimester screening (FTS) for Down syndrome combines measurement of nuchal translucency, free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein-A (PAPP-A). The aim of this study was to undertake a detailed analysis of FTS results in singleton pregnancies conceived using assisted reproductive technologies (ART) and non-ART pregnancies.A record linkage study compared outcomes in 1739 ART-conceived and 50 253 naturally conceived pregnancies.Overall, significantly lower PAPP-A levels were detected in ART pregnancies (0.83 multiples of median, MoM) than in controls (1.00 MoM) (t-test P0.001). This difference remained after excluding complicated pregnancies. Analysis of factors affecting PAPP-A levels suggested fresh compared with frozen embryo transfers and use of artificial cycles compared with natural cycles for frozen transfers were associated with lower values. The adjusted odds ratio (AdjOR) for receiving a false-positive result was 1.71 (95% CI 1.44-2.04; P0.001) for ART pregnancies compared with non-ART pregnancies, and this leads to a higher AdjOR (1.24, 95% CI 1.03-1.49; P = 0.02) for having a chorionic villous sampling (CVS) or amniocentesis.ART pregnancies have reduced FTS PAPP-A levels leading to an increased likelihood of receiving a false-positive result and having a CVS/amniocentesis. Lower PAPP-A may reflect impairment of early implantation with some forms of ART.

Pérez-Jurado, Luis A. [et al.], Array CGH (comparative genomic hybridization) screening of large patient cohorts with mental retardation and/or multiple congenital anomalies (MR/MCA) has led to the identification of a number of new microdeletion and microduplication syndromes. Recently, a recurrent copy number variant (CNV) at chromosome 16p11.2 was reported to occur in up to 1% of autistic patients in three large autism studies. In the screening of 4284 patients with MR/MCA with various array platforms, we detected 22 individuals (14 index patients and 8 family members) with deletions in 16p11.2, which are genomically identical to those identified in the autism studies. Though some patients shared a facial resemblance and a tendency to overweight, there was no evidence for a recognizable phenotype. Autism was not the presenting feature in our series. The assembled evidence indicates that recurrent 16p11.2 deletions are associated with variable clinical outcome, most likely arising from haploinsufficiency of one or more genes. The phenotypical spectrum ranges from MR and/or MCA, autism, learning and speech problems, to a normal phenotype. © 2009 Elsevier Masson SAS. All rights reserved.

BACKGROUND: Microarray genome analysis is realising its promise for improving detection of genetic abnormalities in individuals with mental retardation and congenital abnormality. Copy number variations (CNVs) are now readily detectable using a variety of platforms and a major challenge is the distinction of pathogenic from ubiquitous, benign polymorphic CNVs. The aim of this study was to investigate replacement of time consuming, locus specific testing for specific microdeletion and microduplication syndromes with microarray analysis, which theoretically should detect all known syndromes with CNV aetiologies as well as new ones. METHODS: Genome wide copy number analysis was performed on 117 patients using Affymetrix 250K microarrays. RESULTS: 434 CNVs (195 losses and 239 gains) were found, including 18 pathogenic CNVs and 9 identified as "potentially pathogenic". Almost all pathogenic CNVs were larger than 500 kb, significantly larger than the median size of all CNVs detected. Segmental regions of loss of heterozygosity larger than 5 Mb were found in 5 patients. CONCLUSIONS: Genome microarray analysis has improved diagnostic success in this group of patients. Several examples of recently discovered "new syndromes" were found suggesting they are more common than previously suspected and collectively are likely to be a major cause of mental retardation. The findings have several implications for clinical practice. The study revealed the potential to make genetic diagnoses that were not evident in the clinical presentation, with implications for pretest counselling and the consent process. The importance of contributing novel CNVs to high quality databases for genotype-phenotype analysis and review of guidelines for selection of individuals for microarray analysis is emphasised.

Purpose: To determine whether the provision of additional genetic counseling support could improve the uptake of genetic services by “at-risk” relatives of probands. Methods: The Tasmanian Clinical Genetics Service implemented a specific counseling intervention to a cohort of patients who were diagnosed with a genetic condition with familial implications and compared this with a control cohort who had not experienced the specific counseling intervention. The study involved 150 family members in 19 different kindreds across the two cohorts. The principal outcome measure was the proportion of at-risk relatives who had made contact with the clinical genetics service within 2 years of the diagnosis in the index patient. Results: The proportion of at-risk relatives who made contact with the genetics service was 61% in the intervention cohort compared with 36% in the control cohort (P = 0.01). After controlling for the gender of the at-risk relatives, relatives in the intervention cohort were 2.6 times more likely to make contact with the genetics service (P = 0.02). Conclusions: The provision of increased genetic counseling support significantly increased the proportion of at-risk relatives who made contact with the genetic service. This suggests that the communication of genetic information within families can be enhanced by the provision of increased genetic counseling support.

There is strong evidence for an association between overgrowth disorders such as Beckwith-Wiedemann syndrome and the development of neoplasia. An increased cancer risk has also been observed in individuals with isolated hemihyperplasia. We critically review the evidence for tumour surveillance in Beckwith-Wiedemann syndrome and isolated hemihyperplasia and suggest local practice guidelines.

Anophthalmia and pituitary gland hypoplasia are both debilitating conditions where the underlying genetic defect is unknown in the majority of cases. We identified a patient with bilateral anophthalmia and absence of the optic nerves, chiasm and tracts, as well as pituitary gland hypoplasia and ear anomalies with a de novo apparently balanced chromosomal translocation, 46,XY,t(3;14)(q28;q23.2). Translocation breakpoint analysis using FISH and high-resolution microarray comparative genomic hybridization (CGH) has identified a 9.66 Mb deleted region on the long arm of chromosome 14 which includes the genes BMP4, OTX2, RTN1, SIX6, SIX1, and SIX4. Three other patients with interstitial deletions involving 14q22-23 have been described, all with bilateral anophthalmia, pituitary abnormalities, ear anomalies, and a facial phenotype similar to our patient. OTX2 is involved in ocular developmental defects, and the severity of the ocular phenotype in our patient and the other 14q22-23 deletion patients, suggests this genomic region harbors other gene/s involved in ocular development. BMP4 haploinsufficiency is predicted to contribute to the ocular phenotype on the basis of its expression pattern and observed murine mutant phenotypes. In addition, deletion of BMP4 and SIX6 is likely to contribute to the abnormal pituitary development, and SIX1 deletion may contribute to the ear and other craniofacial features. This indicates that contiguous gene deletion may contribute to the phenotypic features in the 14q22-23 deletion patients.

Department of Dentistry, Royal Children’s Hospital, Melbourne, AustraliaAmelogenesis imperfecta hypoplastic-hypoma-turation with taurodontism (AIHHT) is an auto-somaldominant(AD)traitassociatedwithenameldefectsandenlargedpulpchambers.Inthisstudy,we mapped an AIHHT family to human chromo-some 17 q21-q22 (lod score 3.3) and identify a twobasepair deletion (CT) at nucleotide 560 in DLX3associated with the disease. This mutation causesa frameshift altering the last two amino acids ofthe DNA-binding homeodomain introducing apremature stop codon truncating the proteinby 88 amino acids. This is the first report of amutation within the homeodomain of DLX3.Previous studies have shown a DLX3 mutationoutside the homeodomain associated with tricho-dento-osseous syndrome (TDO) suggesting TDOand some forms of AIHHT are allelic.

We have expressed an EGFP-CENP-A fusion protein in human cells in order to quantitate the level of CENP-A incorporated into normal and variant human centromeres. The results revealed a 3.2-fold difference in the level of CENP-A incorporation into alpha-satellite repeat DNA-based centromeres, with the Y centromere showing the lowest level of all normal human chromosomes. Identification of individual chromosomes revealed a statistically significant, though not absolute, correlation between chromosome size and CENP-A incorporation. Analysis of three independent neocentromeres revealed a significantly reduced level of CENP-A compared to normal centromeres. Truncation of a neocentric marker chromosome to produce a minichromosome further reduced CENP-A levels, indicating a remodelling of centromeric chromatin. These results suggest a role for increased CENP-A incorporation in the faithful segregation of larger chromosomes and support a model of centromere evolution in which neocentromeres represent ancestral centromeres that, through adaptive evolution, acquire satellite repeats to facilitate the incorporation of higher numbers of CENP-A containing nucleosomes, thereby facilitating the assembly of larger kinetochore structures.

Centromere repositioning provides a potentially powerful evolutionary force for reproductive isolation and speciation, but the underlying mechanisms remain ill-defined. An attractive model is through the simultaneous inactivation of a normal centromere and the formation of a new centromere at a hitherto noncentromeric chromosomal location with minimal detrimental effect. We report a two-generation family in which the centromeric activity of one chromosome 4 has been relocated to a euchromatic site at 4q21.3 through the epigenetic formation of a neocentromere in otherwise cytogenetically normal and mitotically stable karyotypes. Strong epigenetic inactivation of the original centromere is suggested by retention of 1.3 megabases of centromeric α-satellite DNA, absence of detectable molecular alteration in chromosome 4-centromereproximal p- and q-arm sequences, and failure of the inactive centromere to be reactivated through extensive culturing or treatment with histone deacetylase inhibitor trichostatin A. The neocentromere binds functionally essential centromere proteins (CENP-A, CENP-C, CENP-E, CENP-I, BUB1, and HP1), although a moderate reduction in CENP-A binding and sister-chromatid cohesion compared with the typical centromeres suggests possible underlying structural/functional differences. The stable mitotic and meiotic transmissibility of this pseudodicentric-neocentric chromosome in healthy individuals and the ability of the neocentric activity to form in a euchromatic site in preference to a preexisting alphoid domain provide direct evidence for an inherent mechanism of human centromere repositioning and karyotype evolution “in progress.” We discuss the wider implication of such a mechanism for meiotic drive and the evolution of primate and other species.

Both nuclear and mitochondrial DNA mutations can cause energy generation disorders. Respiratory chain complex I deficiency is the most common energy generation disorder and a frequent cause of infantile mitochondrial encephalopathies such as Leigh's disease and lethal infantile mitochondrial disease. Most such cases have been assumed to be caused by nuclear gene defects, but recently an increasing number have been shown to be caused by mutations in the mitochondrially encoded complex I subunit genes ND4, ND5, and ND6. We report the first four cases of infantile mitochondrial encephalopathies caused by mutations in the ND3 subunit gene. Three unrelated children have the same novel heteroplasmic mutation (T10158C), only the second mutation reported in ND3, and one has the previously identified T10191C mutation. Both mutations cause disproportionately greater reductions in enzyme activity than in the amount of fully assembled complex I, suggesting the ND3 subunit plays an unknown but important role in electron transport, proton pumping, or ubiquinone binding. Three cases appear to have a de novo mutation, with no mutation detected in maternal relatives. Mitochondrial DNA disease may be considerably more prevalent in the pediatric population than currently predicted and should be considered in patients with infantile mitochondrial encephalopathies and complex I deficiency.

Chromosome microarray analysis has revolutionised the diagnosis of patients with neurocognitive impairment and has resulted in the association of many phenotypes with copy number changes in particular genes.

Objective To determine whether adverse perinatal outcomes are increased in subfertile women. Design Cohort study. Setting Two tertiary assisted reproductive technologies (ART) centers; Victorian births register. Patient(s) Records of women who registered with the clinics (1991–2000), but did not have an infant using ART, were linked to the birth register (1991–2004) to identify singleton non-ART births within 5 years of registration (N = 2171). Controls, matched by maternal age and year of infant's birth, were selected randomly from birth records (N = 4363). Interventions None. Main Outcome Measure(s) Adverse obstetric and perinatal outcomes. Result(s) After adjusting for confounders, compared with controls, subfertile women had increased odds of hypertension or preeclampsia (adjusted odds ratio [OR] 1.29, 1.02–1.61), antepartum hemorrhage (adjusted OR 1.41, 1.05–1.89), perinatal death (adjusted OR 2.19, 1.10–4.36), low birth weight (adjusted OR 1.44, 1.11–1.85), preterm birth Conclusion(s) Subfertile women with singleton births are at increased risk of several adverse outcomes. These risks should be considered during their antenatal care and when analyzing adverse effects of ART.

O ST E R A B ST R A C T S by ex-vivo fluorescent imaging of hESC-CM grafts using an ex-vivo modified langendorff model. Results: Large-scale remuscularization of the infarct was observed in all hESC-CM treated macaques. In contrast to small animal models, the hESC-CM grafts caused ventricular arrhythmias in primate hearts that resolved after a few weeks. The grafts showed progressive but incomplete, maturation over a three-month period. Grafts were perfused by host vasculature, and electromechanical junctions between graft and host myocytes were present within 2 weeks of engraftment. Importantly, grafts showed regular calcium transients that were synchronized to the host electrocardiogram, indicating electromechanical coupling. Conclusion: hESC-CMs can remuscularize substantial amounts of the infarcted monkey heart. These studies support the further use of human cardiomyocytes for heart regeneration and identify ventricular arrhythmias as a hurdle to overcome en route to clinical trials. Disclosure of Interest: None Declared

Within the cerebral palsy syndromes, athetosis is most commonly causally associated with serious perinatal complications. Genetic factors are thought to play a lesser role, although the risk of recurrence in siblings has been suggested to be as high as 10%. We have conducted a clinical study of 22 subjects with a diagnosis of athetoid cerebral palsy and a review of the literature aiming to identify instances of familial recurrence of athetoid cerebral palsy. The birth history, family history, and previous investigations of subjects with athetoid cerebral palsy were studied and subjects were clinically examined for evidence of an underlying genetic etiology. Factors suggesting a genetic cause were specifically sought, such as advanced paternal age, progression of symptoms, and associated congenital abnormalities. No subjects in the study group had similarly affected relatives, and additional features suggesting a genetic cause were not observed. A literature search identified 16 instances of familial recurrence of athetoid cerebral palsy. Familial cases were typically associated with significant spasticity, microcephaly, intellectual disability, seizures, and a lack of history of birth asphyxia, and most could be explained by either autosomal-recessive or X-linked-recessive inheritance. The genetic contribution to athetoid cerebral palsy is small, with an overall risk of recurrence in siblings of about 1%. This risk is lower than previously suggested in the literature. ( J Child Neurol 2001;16:793—797).

Hypoglossia is a rare congenital malformation, occurring either as an isolated malformation or in association with other deformities, particularly limb defects. We describe a female infant with congenital hypoglossia, micrognathia and situs inversus. The main complications were airway compromise and feeding difficulties requiring tracheostomy and gastrostomy. Situs inversus and hypoglossia have been reported together on six previous occasions, with all cases being sporadic. Situs inversus-hypoglossia falls into a spectrum of aetiologically non-specific developmental field defects that includes the Aglossia-adactylia spectrum and the Agnathia-holoprosencephaly spectrum. Situs inversus-hypoglossia may represent a mild form of Agnathia-holoprosencephaly.

Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital neurocutaneous syndrome comprising unilateral cranial lipomas, lipodermoids of the eye and brain abnormalities. A 3-year-old boy who presented at birth with a scalp lipoma and an ipsilateral epibulbar lipodermoid is described. Infantile spasms developed at 9 months of age and cerebral imaging showed thickened and calcified cortex at the right occiput and hemiatrophy of the right hemisphere. These features were consistent with ECCL. Most children with ECCL have significant developmental delay, but we have found that control of seizures was associated with a significant improvement in developmental outcome.

We describe a brother and sister who both had holoprosencephaly, polydactyly, cardiac lesions and a normal karyotype. The parents were first cousins and a diagnosis of pseudotrisomy 13 syndrome is suggested. This report provides further support that the inheritance of pseudotrisomy 13 syndrome is autosomal recessive.

Imprinting, Small Babies and Assisted Reproduction: Genomic imprinting, small babies and assisted reproduction

Recently, a new recurrent translocation, t(12;21)(p13;q22), has been identified in B-cell lineage acute lymphoblastic leukemia (ALL). The translocation results in the fusion of two known genes, ETV6/TEL(12p13) and AML1(21q22), both of which have been shown to be involved in other hematological malignancies. The t(12;21) is virtually undetectable by routine cytogenetics, but the chimeric transcript ETV6-AML1 has been detected in childhood ALL by molecular techniques in up to 36% of cases, making it the most common genetic abnormality in these patients. It has been shown to be associated with a B-precursor phenotype and an excellent prognosis. We tested 66 diagnostic pediatric ALL samples by reverse transcription polymerase chain reaction (RT-PCR) and found evidence of the t(12;21) in 22 (33%). None of these had previously been identified as harboring the t(12;21), although six had karyotypic abnormalities involving either 12p13 or 21q22. ETV6-AML1 expression defined a subgroup of patients characterised by an age of between two and 12 years, B-lineage immunophenotype and non-hyperdiploid DNA content. Our data further support the importance of molecular diagnostic methods in the identification of clinically distinct subgroups of patients with ALL.

Item does not contain fulltext Cantu syndrome is characterized by congenital hypertrichosis, distinctive facial features, osteochondrodysplasia and cardiac defects. By using family-based exome sequencing, we identified a de novo mutation in ABCC9. Subsequently, we discovered novel dominant missense mutations in ABCC9 in 14 of the 16 individuals with Cantu syndrome examined. The ABCC9 protein is part of an ATP-dependent potassium (K(ATP)) channel that couples the metabolic state of a cell with its electrical activity. All mutations altered amino acids in or close to the transmembrane domains of ABCC9. Using electrophysiological measurements, we show that mutations in ABCC9 reduce the ATP-mediated potassium channel inhibition, resulting in channel opening. Moreover, similarities between the phenotype of individuals with Cantu syndrome and side effects from the K(ATP) channel agonist minoxidil indicate that the mutations in ABCC9 result in channel opening. Given the availability of ABCC9 antagonists, our findings may have direct implications for the treatment of individuals with Cantu syndrome.

A 33-year-old man with WAGR syndrome is described with morbid obesity associated with hyperphagia and an apparent lack of satiety. It is possible that a gene associated with satiety is present at 11p13 although it is premature to conclude that obesity is a specific feature of WAGR syndrome.

Many exome sequencing studies of Mendelian disorders fail to optimally exploit family information. Classical genetic linkage analysis is an effective method for eliminating a large fraction of the candidate causal variants discovered, even in small families that lack a unique linkage peak. We demonstrate that accurate genetic linkage mapping can be performed using SNP genotypes extracted from exome data, removing the need for separate array-based genotyping. We provide software to facilitate such analyses.

Methylation analysis of fragile X-related epigenetic elements may provide a suitable newborn screening test for fragile X syndrome

BackgroundSubtelomeric deletions of the long arm of chromosome 20 are rare, with only 11 described in the literature. Clinical features of individuals with these microdeletions include severe limb malformations, skeletal abnormalities, growth retardation, developmental and speech delay, mental retardation, seizures and mild, non-specific dysmorphic features.Methodology/principal findingsWe characterized microdeletions at 20q13.33 in six individuals referred for genetic evaluation of developmental delay, mental retardation, and/or congenital anomalies. A comparison to previously reported cases of 20q13.33 microdeletion shows phenotypic overlap, with clinical features that include mental retardation, developmental delay, speech and language deficits, seizures, and behavior problems such as autistic spectrum disorder. There does not appear to be a clinically recognizable constellation of dysmorphic features among individuals with subtelomeric 20q microdeletions.Conclusions/significanceBased on genotype-phenotype correlation among individuals in this and previous studies, we discuss several possible candidate genes for specific clinical features, including ARFGAP1, CHRNA4 and KCNQ2 and neurodevelopmental deficits. Deletion of this region may play an important role in cognitive development.

Nature Genetics 39, 1488–1493 (2007); published online 11 November 2007; corrected after print 23 January 2008 In the version of this article initially published, the affiliation for C S Raman was incorrect. Dr. Raman is affiliated with the Department of Biochemistry and Molecular Biology at the University of Texas Health Science Center, and not with the Structural Biology Center.