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The presence of oligoclonal immunoglobulin bands in the cerebrospinal fluid (CSF) has long been rec- ognised as a characteristic manifestation of the immune dysregulation underlying multiple sclerosis (MS). However, it remains unclear how or why these bands develop, and little is known about the nature of the aberrantly expanded B cell clones that produce these immunoglobulins. To explore these questions we have performed single-cell RNA sequencing in CSF (108,219 cells) and PBMCs (232,587 cells) obtained from 104 individuals; 66 with multiple sclerosis, 25 with Non-Inflammatory Neurological Conditions (NINCs) and 13 with other Inflammatory Neurological Conditions (INCs).We found that MS CSF harbours an 8-fold higher proportion of plasma cells than control CSF. Plasma cells in the MS CSF up-regulate diverse pathways implicated in pro-inflammatory signalling and antibody synthesis, including TNFα and mTORC1 signalling, compared with their peripheral counterparts.We identified a large number of clonally-expanded cells in the MS CSF which are largely IgG+ plasma cells with evidence of intrathecal antigen experience. These clonally-expanded cells display clonal connections to the periphery.Our findings elucidate the phenotype of a critical cell population in MS biology – clonally-expanded CSF plasma cells. These insights have potential diagnostic and therapeutic implications, and may lead to more general insights into B cell autoimmunity.

Genome-wide association studies (GWAS) have identified over 100 loci containing single nucleotide variants (SNVs) that influence the risk of developing multiple sclerosis (MS). Most of these loci lie in non-coding regulatory regions of the genome that are active in immune cells and are therefore thought to modify risk by altering the expression of key immune genes. To explore this hypothesis we screened genes flanking MS-associated variants for evidence of allele specific expression (ASE) by quantifying the transcription of coding variants in linkage disequilibrium with MS-associated SNVs. In total, we were able to identify and successfully analyse 200 such coding variants (from 112 genes) in both CD4+ and CD8+ T cells from 106 MS patients and 105 controls. Fifty-six of these coding variants (from 43 genes) showed statistically significant evidence of ASE in one or both cell types. In the Lck interacting transmembrane adaptor 1 gene (LIME1), for example, we were able to show that in both cell types, the MS-associated variant rs2256814 increased the expression of some transcripts while simultaneously reducing the expression of other transcripts. In CD4+ cells from an additional independent set of 96 cases and 93 controls we were able to replicate the effect of this SNV on the balance of alternate LIME1 transcripts using qPCR (p = 5 × 10-24). Our data thus indicate that some of the MS-associated SNVs identified by GWAS likely exert their effects on risk by distorting the balance of alternate transcripts rather than by changing the overall level of gene expression.

The Saguenay-Lac-Saint-Jean (SLSJ) region is located in northeastern Quebec and is known for its unique demographic history and founder effect. As founder populations are enriched with population-specific variants, we characterized the variants distribution in SLSJ and compared it with four European populations (Finnish, Sweden, United Kingdom and France), of which the Finnish population is another founder population. Targeted sequencing of the coding and non-coding immune regulatory regions of the SLSJ asthma familial cohort and the four European populations were performed. Rare and low-frequency coding and non-coding regulatory variants identified in the SLSJ population were then investigated for variant- and gene-level associations with asthma and allergy-related traits (eosinophil percentage, immunoglobulin (Ig) E levels and lung function). Our data showed that (1) rare or deleterious variants were not enriched in the two founder populations as compared with the three non-founder European populations; (2) a larger proportion of founder population-specific variants occurred with higher frequencies; and (3) low-frequency variants appeared to be more deleterious. Furthermore, a rare variant, rs1386931, located in the 3'-UTR of CXCR6 and intron of FYCO1 was found to be associated with eosinophil percentage. Gene-based analyses identified NRP2, MRPL44 and SERPINE2 to be associated with various asthma and allergy-related traits. Our study demonstrated the usefulness of using a founder population to identify new genes associated with asthma and allergy-related traits; thus better understand the genes and pathways implicated in pathophysiology.

Background: In less than a decade, genomewide association studies have identified over 100 single-nucleotide variants that are associated with increased risk of developing multiple sclerosis. However, since these studies have focused almost exclusively on European populations, it is unclear what role these variants might play in determining risk in other ethnic groups. Objective: To assess the effects of European multiple sclerosis–associated risk variants in the south Asian population. Methods: Using a combination of chip-based genotyping and next-generation sequencing, we have assessed 109 European-associated variants in a total of 270 cases and 555 controls from the south Asian population. Results: We found that two-thirds of the tested variants (72/109) showed over representation of the European risk allele in south Asian cases ( p Conclusion: Our data indicate substantial overlap in genetic risk architecture between Europeans and south Asians and suggest that the aetiology of the disease may be largely independent of ethnicity.

Multiple sclerosis is a common, complex neurological disease, where almost 20% of risk heritability can be attributed to common genetic variants, including >230 identified by genome-wide association studies (Patsopoulos et al., 2017). Multiple strands of evidence suggest that the majority of the remaining heritability is also due to the additive effects of individual variants, rather than epistatic interactions between these variants, or mutations exclusive to individual families. Here, we show in 68,379 cases and controls that as much as 5% of this heritability is explained by low-frequency variation in gene coding sequence. We identify four novel genes driving MS risk independently of common variant signals, which highlight a key role for regulatory T cell homeostasis and regulation, IFNγ biology and NFκB signaling in MS pathogenesis. As low-frequency variants do not show substantial linkage disequilibrium with other variants, and as coding variants are more interpretable and experimentally tractable than non-coding variation, our discoveries constitute a rich resource for dissecting the pathobiology of MS.

Supported by grants (2011/R/13 and 2015/R/09, to Dr. Cucca) from the Italian Foundation for Multiple Sclerosis; contracts (N01-AG-1-2109 and HHSN271201100005C, to Dr. Cucca) from the Intramural Research Program of the National Institute on Aging, National Institutes of Health (NIH); a grant (FaReBio2011 “Farmaci e Reti Biotecnologiche di Qualità,” to Dr. Cucca) from the Italian Ministry of Economy and Finance; a grant (633964, to Dr. Cucca) from the Horizon 2020 Research and Innovation Program of the European Union (...), Steri, M.; Orru, V.; Idda, M. L.; Pitzalis, M.; Pala, M.; Zara, I.; Sidore, C.; Faa, V.; Floris, M.; Deiana, M.; Asunis, I.; Porcu, E.; Mulas, A.; Piras, M. G.; Lobina, M.; Lai, S.; Marongiu, M.; Serra, V.; Marongiu, M.; Sole, G.; Busonero, F.; Maschio, A.; Cusano, R.; Cuccuru, G.; Deidda, F.; Poddie, F.; Farina, G.; Dei, M.; Virdis, F.; Olla, S.; Satta, M. A.; Pani, M.; Delitala, A.; Cocco, E.; Frau, J.; Coghe, G.; Lorefice, L.; Fenu, G.; Ferrigno, P.; Ban, M.; Barizzone, N.; Leone, M.; Guerini, F. R.; Piga, M.; Firinu, D.; Kockum, I.; Bomfim, I. Lima; Olsson, T.; Alfredsson, L.; Suarez, A.; Carreira, P. E.; Castillo-Palma, M. J.; Marcus, J. H.; Congia, M.; Angius, A.; Melis, M.; Gonzalez, A.; Riquelme, M. E. A.; da Silva, B. M.; Marchini, M.; Danieli, M. G.; Del Giacco, S.; Mathieu, A.; Pani, A.; Montgomery, S. B.; Rosati, G.; Hillert, J.; Sawcer, S.; D'Alfonso, S.; Todd, J. A.; Novembre, J.; Abecasis, G. R.; Whalen, M. B.; Marrosu, M. G.; Meloni, A.; Sanna, S.; Gorospe, M.; Schlessinger, D.; Fiorillo, E.; Zoledziewska, M.; Cucca, F.

We assembled and analyzed genetic data of 47,351 multiple sclerosis (MS) subjects and 68,284 control subjects and establish a reference map of the genetic architecture of MS that includes 200 autosomal susceptibility variants outside the major histocompatibility complex (MHC), one chromosome X variant, and 32 independent associations within the extended MHC. We used an ensemble of methods to prioritize up to 551 potentially associated MS susceptibility genes, that implicate multiple innate and adaptive pathways distributed across the cellular components of the immune system. Using expression profiles from purified human microglia, we do find enrichment for MS genes in these brain - resident immune cells. Thus, while MS is most likely initially triggered by perturbation of peripheral immune responses the functional responses of microglia and other brain cells are also altered and may have a role in targeting an autoimmune process to the central nervous system.One Sentence Summary:We report a detailed genetic and genomic map of multiple sclerosis, and describe the role of putatively affected genes in the peripheral immune system and brain resident microglia.

Genome-wide association studies have revolutionised the genetic analysis of multiple sclerosis. Through international collaborative efforts involving tens of thousands of cases and controls, more than 100 associated common variants have now been identified. These variants consistently implicate genes associated with immunological processes, overwhelmingly lie in regulatory rather than coding regions, and are frequently associated with other autoimmune diseases. The functional implications of these associated variants are mostly unknown; however, early work has shown that several variants have effects on splicing that result in meaningful changes in the balance between different isoforms in relevant tissues. Including the well established risk attributable to variants in genes encoding human leucocyte antigens, only about a quarter of reported heritability can now be accounted for, suggesting that a substantial potential for further discovery remains.

Carriers of mutations in the glucocerebrosidase gene (GBA) are at increased risk of developing Parkinson's disease. The frequency of GBA mutations in unselected Parkinson's disease populations has not been established. Furthermore, no previous studies have investigated the influence of GBA mutations on the natural history of Parkinson's disease using prospective follow-up. We studied DNA from 262 cases who had been recruited at diagnosis into one of two independent community-based incidence studies of Parkinson's disease. In 121 cases, longitudinal data regarding progression of motor disability and cognitive function were derived from follow-up assessments conducted every 18 months for a median of 71 months. Sequencing of the GBA was performed after two-stage polymerase chain reaction amplification. The carrier frequency of genetic variants in GBA was determined. Baseline demographic and clinical variables were compared between cases who were either GBA mutation carriers, polymorphism carriers or wild-type homozygotes. Cox regression analysis was used to model progression to major motor (Hoehn and Yahr stage 3), and cognitive (dementia) end-points in cases followed longitudinally. We show that in a representative, unselected UK Parkinson's disease population, GBA mutations are present at a frequency of 3.5%. This is higher than the prevalence of other genetic mutations currently associated with Parkinson's disease and indicates that GBA mutations make an important contribution to Parkinson's disease encountered in the community setting. Baseline clinical characteristics did not differ significantly between cases with and without GBA sequence variants. However, the hazard ratio for progression both to dementia (5.7, P = 0.003) and Hoehn and Yahr stage 3 (4.2, P = 0.003) were significantly greater in GBA mutation carriers. We also show that carriers of polymorphisms in GBA which are not generally considered to increase Parkinson's disease risk are at significantly increased risk of progression to Hoehn and Yahr stage 3 (3.2, P = 0.004). Our results indicate that genetic variation in GBA has an important impact on the natural history of Parkinson's disease. To our knowledge, this is the first time a genetic locus has been shown to influence motor progression in Parkinson's disease. If confirmed in further studies, this may indicate that GBA mutation status could be used as a prognostic marker in Parkinson's disease. Elucidation of the molecular mechanisms that underlie this effect will further our understanding of the pathogenesis of the disease and may in turn suggest novel therapeutic strategies.

It is not known how 5-HTTLPR genotype × childhood adversity (CA) interactions that are associated with an increased risk for affective disorders in population studies operate at the neural systems level. We hypothesized that healthy adolescents at increased genetic and environmental risk for developing mood disorders (depression and anxiety) would demonstrate increased amygdala reactivity to emotional stimuli compared to those with only one such risk factor or those with none. Participants (n = 67) were classified into one of 4 groups dependent on being homozygous for the long or short alleles within the serotonin-transporter-linked polymorphic region (5-HTTLPR) of the SLC6A4 gene and exposure to CA in the first 11 years of life (present or absent). A functional magnetic resonance imaging investigation was undertaken which involved viewing emotionally-salient face stimuli. In addition, we assessed the role of other variables hypothesized to influence amygdala reactivity, namely recent negative life-events (RNLE) assessed at ages 14 and 17, current anxiety symptoms and psychiatric history. We replicated prior findings demonstrating moderation by gene variants in 5-HTTLPR, but found no support for an effect of CA on amygdala reactivity. We also found a significant effect of RNLE aged 17 with amygdala reactivity demonstrating additive, but not interactive effects with 5-HTTLPR. A whole-brain analysis found a 5-HTTLPR × CA interaction in the lingual gyrus whereby CA appears to differentially modify neural reactivity depending on genotype. These results demonstrate that two different forms of environmental adversities interplay with 5-HTTLPR and thereby differentially impact amygdala and cortical reactivity., Highlights ► Tested hypothesis that amygdala is neural locus for 5-HTTLPR × environment interaction ► Additive effects of 5-HTTLPR genotype and recent life events on amygdala reactivity ► Genotype × childhood adversity interaction on neural reactivity in lingual gyrus ► Two forms of environmental adversities interplay with 5-HTTLPR and neural reactivity. ► No support for hypothesized G × E interaction on amygdala reactivity

International audience; Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.

Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.

Background: Key questions about the interaction between the serotonin transporter length polymorphism (5-HTTLPR) and stress in the etiology of depression remain unresolved. We test the hypotheses that the interaction is restricted to childhood maltreatment (as opposed to stressful events in adulthood), and leads to chronic depressive episodes (as opposed to any onset of depression), using gold-standard assessments of childhood maltreatment, severe life events, chronic depression, and new depressive onsets. Method: In a risk-enriched sample of 273 unrelated women, childhood maltreatment was retrospectively assessed with the Childhood Experience of Care and Abuse (CECA) interview and 5-HTTLPR was genotyped. A subset of 220 women was followed prospectively for 12 months with life events assessed with the Life Events and Difficulties (LEDS) interview. Any chronic episode of depression (12 months or longer) during adulthood and onset of a major depressive episode during a 12-month follow-up were established with the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) interview. Results: The short alleles of 5-HTTLPR moderated the relationship between childhood maltreatment and chronic depression in adulthood, reflected in a significant gene–environment interaction (RD = 0.226, 95% CI: 0.076– 0.376, P = .0032). 5-HTTLPR did not moderate the effects of either childhood maltreatment or severe life events on new depressive onsets. Conclusions: The short variant of the serotonin transporter gene specifically sensitizes to the effect of early-life experience of abuse or neglect on whether an adult depressive episode takes a chronic course. This interaction may be responsible for a substantial proportion of cases of chronic depression in the general population. Depression and

Background: Parkinson's disease (PD) is a common neurodegenerative disorder of unknown etiology. The characteristic α-synuclein aggregation of PD is also a feature of Sanfilippo syndrome, a storage disorder caused by α-N-acetylglucosaminidase (NAGLU) gene mutations. We explored genetic links between these disorders and studied the pathology of Sanfilippo syndrome to investigate a common pathway toward α-synuclein aggregation. Methods: We typed the 2 single-nucleotide polymorphisms that tag the common haplotypes of NAGLU in 926 PD patients and 2308 controls and also stained cortical tissue from 2 cases of Sanfilippo A syndrome using the anti-α-synuclein antibody, Per7. Results: Allelic analysis showed an association between rs2071046 and risk for PD (P 1.3 × 10−3). Intracellular α-synuclein accumulation was observed in the cortical tissue of both Sanfilippo A syndrome cases. Conclusions: This study suggests a possible role of NAGLU in susceptibility to PD while extending evidence for α-synuclein aggregation in the brain in lysosomal storage disorders. Our findings support a mechanism involving lysosomal dysfunction more generally in the pathogenesis of PD. © 2011 Movement Disorder Society

Background: The environmental influence of sun exposure and vitamin D in particular and its implication with multiple sclerosis (MS) has recently received considerable attention. Current evidence based on genetic and epidemiological studies indicate that vitamin D is implicated in the aetiology of this disease. Methods: We examined two common variants in the vitamin D receptor ( VDR) gene in 1153 trio families and 726 cases and 604 controls. We also examined epistatic interactions between the VDR SNPs rs731236 and rs2228570 with the tagging single nucleotide polymorphism (SNP) rs3135388 for the HLA-DRB*1501 locus containing a highly conserved vitamin D responsive element within its promoter region. Results: We found weak evidence for an association between the rs731236C allele and MS, while there was no direct association with rs2228570. When examining the interaction between the VDR gene variations and the DRB1*1501 tagging SNP a more complex relationship was observed. Although the interaction was not statistically significant, there appeared to be a trend of increasing risk of MS in participants who were homozygous for the HLA-DRB1*1501 allele in association with the more active form of the VDR (Fok1). Conclusion: We have identified weak evidence of an association between a common variation within the VDR gene and MS, in the largest study reported to date of this candidate gene. There appears to be a relationship between polymorphisms in the VDR and the risk of MS, which is potentially modified by HLA-DRB1*1501.

Background The association of HLA A*02 with multiple sclerosis (MS) was recently confirmed by the authors, and it was observed that the combined presence of HLA Cw*05 significantly enhanced (threefold) the protective effect of HLA A*02 . Objectives and methods Since A*02 - Cw*05 is carried by two HLA extended haplotypes characterised by the B*4402 and B*1801 alleles, respectively, the association analysis was extended to HLA B*44 and B*18 in an Italian sample (1445 MS cases and 973 controls) and these associations were verified in a UK cohort (721 MS cases, 408 controls and 480 family trios). Results A strong protective effect, independent of DR15 , of the A*02 - Cw*05 combination carrying B*44 (OR 0.27, p=3.3×10 -5 ) was seen in the Italian samples and confirmed in UK family trios (OR 0.33, p=5.5×10 -4 ) and in a combined cohort of UK families and case–controls (OR 0.53, p=0.044). This protective effect was significantly stronger than that mediated by A*02 alone. Logistic regression showed that A*02 - Cw*05 maintained a significant protection when adjusted for B alleles (Italy: OR 0.38, p=6.5×10 -7 ; UK: OR 0.60, p=0.0029), indicating that it was not secondary to linkage disequilibrium with B*44 . Different from A*02 , the other HLA class I tested markers individually showed no significant ( Cw*05 , B*18) or a modest (B*44) protection when adjusted for the remaining markers. Conclusions This study identified at least two independent protective effects which are tagged by A*02–Cw*05 and A*02 , respectively. Further studies are needed to elucidate whether this protective effect is due to the presence of an unanalysed factor characterising the HLA extended haplotype(s) carrying A*02 and Cw*05 or to a direct interaction between these alleles.

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a hereditary cause of cerebral small-vessel disease associated with one of many recognised mutations of the NOTCH3 gene. Spinal cord involvement is not a recognised feature. The authors describe a unique CADASIL pedigree that manifested a stereotypical pattern of cord lesions, in association with a novel and atypical NOTCH3 mutation. METHODS: Clinical, radiological, laboratory and genetic characterisation of three affected family members. The associated NOTCH3 mutation was further evaluated by site-directed mutagenesis, immunohistochemistry, CBF1-transcription reporter assay, and screened for in 100 unrelated pathologically confirmed multiple sclerosis (MS) patients. RESULTS: Three members of a family presented with CADASIL caused by a novel NOTCH3 missense mutation, C212Y. Two daughters of the proband also manifested a distinctive pattern of cord lesions confined to the posterocentral zone, cerebral lesions showing both a demyelinating and a typical CADASIL topography, positive antinuclear antibodies and intrathecally derived oligoclonal bands. The mutation occurred in exon 4--that is, outside the Notch3 ligand-binding domain--yet unusually for this location impaired Notch function as assessed by Jagged1 signal transduction. The C212Y mutation did not occur in 100 separate MS cases. CONCLUSIONS: This is the first description of an inherited pattern of cord lesions in association with CADASIL. The fact that certain features of dysregulated immunity also occurred, in association with a novel and atypical loss-of-function NOTCH3 mutation, supports evidence for functional interactions of Notch3 with the immune system, in addition to its vascular support role.

Genomewide association studies have implicated the CLEC16A gene in several autoimmune diseases, including multiple sclerosis (MS) and type 1 diabetes. However, the most associated single-nucleotide polymorphism (SNP) varies, and causal variants are still to be defined. In MS, two SNPs in partial linkage disequilibrium with each other, rs6498169 and rs12708716, have been validated at genomewide significance level. To explore the CLEC16A association in MS in more detail, we genotyped 57 SNPs in 807 Norwegian MS patients and 1027 Norwegian controls. Six highly associated SNPs emerged and were then replicated in two large independent sample sets (Norwegian and British), together including 1153 MS trios, 2308 MS patients and 4044 healthy controls. In combined analyses, SNP rs12708716 gave the strongest association signal in MS (P=5.3 x 10⁻⁸, odds ratio 1.18, 95% confidence interval=1.11-1.25), and was found to be superior to the other SNP associations in conditional logistic regression analyses. Expression analysis revealed that rs12708716 genotype was significantly associated with the relative expression levels of two different CLEC16A transcripts in thymus (P=0.004), but not in blood, possibly implying a thymus- or cell-specific splice regulation.

BackgroundThere is increasing evidence for genetic effects on the hypothalamic–pituitary axis system. More than one gene is likely to moderate corticoid-mediated activity.AimsTo investigate whether the brain-derived neurotrophic factor (BDNF) polymorphism (rs6265, Val66Met) is associated with morning waking salivary cortisol and moderates the corticoid-mediated risk for subsequent depressive episode onset independently of the known effects of 5-HTTLPR (the serotonin transporter gene promoter).MethodHigh-risk adolescents (n = 401) were genotyped for Val66Met BDNF and 5-HTTLPR. Salivary samples were obtained on four consecutive school days within 1 h of waking. There were 365 (91%) remaining participants reassessed at 12 months for episodes of psychiatric disorder in the follow-up period. Of these, 357 (89%) had complete data for multivariate modelling.ResultsThere were 41 (11.2%) individuals who reported a new episode of clinical depression over the follow-up period. Increased risk for subsequent depression was found in carriers of the Val66Val genotype in BDNF with higher morning waking cortisol. This remained present when the known interaction between carriers of a short allele of 5-HTTLPR with higher morning salivary cortisol was taken into account.ConclusionsBoth BDNF and 5-HTTLPR genes show evidence of modifying the risk of a subsequent new depressive episode associated with elevated morning salivary cortisol. In adolescents morning salivary cortisol levels may constitute a biomarker for some forms of unipolar depression.

Several single-nucleotide polymorphism (SNP) genome-wide association studies (GWASs) have been completed in multiple sclerosis (MS). Follow-up studies of the variants with the most promising rankings, especially when supplemented by informed candidate gene selection, have proven to be extremely successful. In this study we report the results of a multi-stage replication analysis of the putatively associated SNPs identified in the Wellcome Trust Case Control Consortium non-synonymous SNP (nsSNP) screen. In total, the replication sample consisted of 3444 patients and 2595 controls. A combined analysis of the nsSNP screen and replication data provides evidence implicating a novel additional locus, rs3748816 in membrane metalloendopeptidase-like 1 (MMEL1; odds ratio=1.16, P=3.54 × 10⁻⁶) in MS susceptibility.

Genome-wide association studies (GWASs) have proven highly effective, identifying hundreds of associations across numerous complex diseases. These studies typically test hundreds of thousands of variations and identify hundreds of potential associations. However, to date, follow-up attempts have generally only concentrated on just the few most significant initial associations, leaving the majority of true associations in any GWAS study without replication. Here, we present a substantially more comprehensive follow-up of the first genome-wide association screen performed in multiple sclerosis (MS), a complex genetic disease with central nervous system inflammation. We genotyped approximately 30 000 single-nucleotide polymorphisms (SNPs) that demonstrated mild-to-moderate levels of significance (Por = 0.10) in the initial GWAS in an independent set of 1343 MS cases and 1379 controls. We further replicated several of the most significant findings in another independent data set of 2164 MS cases and 2016 controls. We find considerable evidence for a number of novel susceptibility loci including KIF21B [rs12122721, combined P = 6.56 x 10(-10), odds ratio (OR) = 1.22] and TMEM39A (rs1132200, P = 3.09 x 10(-8), OR = 1.24), both of which meet genome-wide significance. Both of these loci were overlooked in the initial replication, despite being among the top 3000 ( approximately 1%) SNP hits in the original screen.

Cognitive abnormalities are common in Parkinson's disease, with important social and economic implications. Factors influencing their evolution remain unclear but are crucial to the development of targeted therapeutic strategies. We have investigated the development of cognitive impairment and dementia in Parkinson's disease using a longitudinal approach in a population-representative incident cohort (CamPaIGN study, n = 126) and here present the 5-year follow-up data from this study. Our previous work has implicated two genetic factors in the development of cognitive dysfunction in Parkinson's disease, namely the genes for catechol-O-methyltransferase (COMT Val(158)Met) and microtubule-associated protein tau (MAPT) H1/H2. Here, we have explored the influence of these genes in our incident cohort and an additional cross-sectional prevalent cohort (n = 386), and investigated the effect of MAPT H1/H2 haplotypes on tau transcription in post-mortem brain samples from patients with Lewy body disease and controls. Seventeen percent of incident patients developed dementia over 5 years [incidence 38.7 (23.9-59.3) per 1000 person-years]. We have demonstrated that three baseline measures, namely, age >or=72 years, semantic fluency less than 20 words in 90 s and inability to copy an intersecting pentagons figure, are significant predictors of dementia risk, thus validating our previous findings. In combination, these factors had an odds ratio of 88 for dementia within the first 5 years from diagnosis and may reflect the syndrome of mild cognitive impairment of Parkinson's disease. Phonemic fluency and other frontally based tasks were not associated with dementia risk. MAPT H1/H1 genotype was an independent predictor of dementia risk (odds ratio = 12.1) and the H1 versus H2 haplotype was associated with a 20% increase in transcription of 4-repeat tau in Lewy body disease brains. In contrast, COMT genotype had no effect on dementia, but a significant impact on Tower of London performance, a frontostriatally based executive task, which was dynamic, such that the ability to solve this task changed with disease progression. Hence, we have identified three highly informative predictors of dementia in Parkinson's disease, which can be easily translated into the clinic, and established that MAPT H1/H1 genotype is an important risk factor with functional effects on tau transcription. Our work suggests that the dementing process in Parkinson's disease is predictable and related to tau while frontal-executive dysfunction evolves independently with a more dopaminergic basis and better prognosis.

BackgroundThe short (s) allele of the serotonin transporter gene promoter (5-HTTLPR) may be associated with exposure to social adversities and the subsequent onset of depressive illness in adulthood.AimsTo test in adolescents at high risk for depression whether the short ‘s’ allele is associated with levels of morning cortisol and the subsequent onset of a depressive episode.MethodHigh-risk adolescents (n = 403) were genotyped for 5-HTTLPR. Salivary samples were obtained on four consecutive school days within 1 h of waking from 393 (97.5%) individuals and 367 (91%) underwent a mental state reassessment at 12 months.ResultsMultilevel analysis revealed higher levels of salivary cortisol in short allele carriers (s/s>s/l>l/l). A subsequent episode of depression was increased in those with higher cortisol and the ‘s’ allele, and independently by depressive symptoms at entry, in both genders.ConclusionsThe short allele of 5-HTTLPR may moderate the association between morning cortisol and the subsequent onset of a depressive episode.

Familial clustering of autoimmune disease is well recognized and raises the possibility that some susceptibility genes may predispose to autoimmunity in general. In light of this observation, it might be expected that some of the variants of established relevance in one autoimmune disease may also be relevant in other related conditions. On the basis of this hypothesis, we tested seven single nucleotide polymorphisms (SNPs) that are known to be associated with type I diabetes in a large multiple sclerosis data set consisting of 2369 trio families, 5737 cases and 10 296 unrelated controls. Two of these seven SNPs showed evidence of association with multiple sclerosis; that is rs12708716 from the CLEC16A gene (P=1.6 x 10(-16)) and rs763361 from the CD226 gene (P=5.4 x 10(-8)). These findings thereby identify two additional multiple sclerosis susceptibility genes and lend support to the notion of autoimmune susceptibility genes. ispartof: Genes and immunity vol:10 issue:1 pages:11-14 ispartof: location:England status: published