We carried out a genome wide association study of type-2 diabetes (T2D) amongst 20,119 people of South Asian ancestry (5,561 with T2D); we identified 20 independent SNPs associated with T2D at P<10−4 for testing amongst a further 38,568 South Asians (13,170 with T2D). In combined analysis, common genetic variants at six novel loci (GRB14, ST6GAL1, VPS26A, HMG20A, AP3S2 and HNF4A) were associated with T2D (P=4.1×10−8 to P=1.9×10−11); SNPs at GRB14 were also associated with insulin sensitivity, and at ST6GAL1 and HNF4A with pancreatic beta-cell function respectively. Our findings provide additional insight into mechanisms underlying T2D, and demonstrate the potential for new discovery from genetic association studies in South Asians who have increased susceptibility to T2D.

Examining complete gene knockouts within a viable organism can inform on gene function. We sequenced the exomes of 3,222 British Pakistani-heritage adults with high parental relatedness, discovering 1,111 rare-variant homozygous genotypes with predicted loss of gene function (knockouts) in 781 genes. We observed 13.7% fewer than expected homozygous knockout genotypes, implying an average load of 1.6 recessive-lethal-equivalent LOF variants per adult. Linking genetic data to lifelong health records, knockouts were not associated with clinical consultation or prescription rate. In this dataset we identified a healthy PRDM9 knockout mother, and performed phased genome sequencing on her, her child and controls, which showed meiotic recombination sites localised away from PRDM9-dependent hotspots. Thus, natural LOF variants inform upon essential genetic loci, and demonstrate PRDM9 redundancy in humans.

Multiple sclerosis is a common disease with proven heritability, but, despite large-scale attempts, no underlying risk genes have been identified. Traditional linkage scans have so far identified only one risk haplotype for multiple sclerosis (at HLA on chromosome 6), which explains only a fraction of the increased risk to siblings. Association scans such as admixture mapping have much more power, in principle, to find the weak factors that must explain most of the disease risk. We describe here the first high-powered admixture scan, focusing on 605 African American cases and 1,043 African American controls, and report a locus on chromosome 1 that is significantly associated with multiple sclerosis.

A 5-year follow-up study was performed on 89 patients who had undergone brain magnetic resonance imaging (MRI) at presentation with an acute clinically isolated syndrome of the optic nerves, brainstem or spinal cord of a type suggestive of multiple sclerosis. At presentation, MRI was abnormal, revealing one or more asymptomatic cerebral white matter lesions in 57 (64%), and was normal in 32 (36%). At follow-up, progression to clinically definite multiple sclerosis had occurred in 37 out of 57 (65%) with an abnormal MRI and one out of 32 (3%) with normal MRI. Human leucocyte antigen (HLA) typing was performed in 70 patients and cerebrospinal fluid (CSF) was examined at presentation in 36. The presence of HLA-DR2 antigen or cerebrospinal fluid oligoclonal IgG bands were both associated with a significantly increased risk of progression to multiple sclerosis, but MRI was much more powerful in predicting outcome. The presence of four or more MRI lesions at presentation was associated with a higher rate of progression to multiple sclerosis, more frequent development of moderate or severe disabilities and a greater number of new MRI lesions at follow-up. The results indicate that brain MRI at presentation with a clinically isolated syndrome suggestive of multiple sclerosis is a powerful predictor of the clinical course over the next 5 years. This observation, combined with an ability to detect other sometimes treatable disorders which can also cause such syndromes, suggests that MRI is the investigation of choice in evaluating this group of patients.

We performed a genome-wide association study (GWAS) and a multistage meta-analysis of type 2 diabetes (T2D) in Punjabi Sikhs from India. Our discovery GWAS in 1,616 individuals (842 case subjects) was followed by in silico replication of the top 513 independent single nucleotide polymorphisms (SNPs) (P < 10−3) in Punjabi Sikhs (n = 2,819; 801 case subjects). We further replicated 66 SNPs (P < 10−4) through genotyping in a Punjabi Sikh sample (n = 2,894; 1,711 case subjects). On combined meta-analysis in Sikh populations (n = 7,329; 3,354 case subjects), we identified a novel locus in association with T2D at 13q12 represented by a directly genotyped intronic SNP (rs9552911, P = 1.82 × 10−8) in the SGCG gene. Next, we undertook in silico replication (stage 2b) of the top 513 signals (P < 10−3) in 29,157 non-Sikh South Asians (10,971 case subjects) and de novo genotyping of up to 31 top signals (P < 10−4) in 10,817 South Asians (5,157 case subjects) (stage 3b). In combined South Asian meta-analysis, we observed six suggestive associations (P < 10−5 to < 10−7), including SNPs at HMG1L1/CTCFL, PLXNA4, SCAP, and chr5p11. Further evaluation of 31 top SNPs in 33,707 East Asians (16,746 case subjects) (stage 3c) and 47,117 Europeans (8,130 case subjects) (stage 3d), and joint meta-analysis of 128,127 individuals (44,358 case subjects) from 27 multiethnic studies, did not reveal any additional loci nor was there any evidence of replication for the new variant. Our findings provide new evidence on the presence of a population-specific signal in relation to T2D, which may provide additional insights into T2D pathogenesis.

patients with "true" OCB negative multiple sclerosis were significantly less disabled than matched OCB positive controls. Re-examination of CSF-serum pairs from six OCB negative patients showed that three remained OCB negative while three showed evidence of intrathecal synthesis of OCBs. Conclusions-OCB negative clinically definite multiple sclerosis is rare and should be diagnosed with caution; in unequivocal cases it seems to have a relatively benign prognosis.

We have demonstrated that 13 variants confer an increased risk of type 2 diabetes in our Pakistani populations; to our knowledge this is the first time that SNPs in or near KCNQ1, JAZF1, IRS1, KLF14, CHCHD9 and DUSP9 have been significantly associated with the disease in South Asians. Large-scale studies and meta-analyses of South Asian populations are needed to further confirm the effect of these variants in this ethnic group.

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