Human Genetics And Molecular Medicine - Research Publications
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Item Shared and unique common genetic determinants between pediatric and adult celiac disease(BioMed Central Ltd., 2016) Senapati, S.; Sood, A.; Midha, V.; Sood, N.; Sharma, S.; Kumar, L.; Thelma, B.K.Background: Based on age of presentation, celiac disease (CD) is categorised as pediatric CD and adult CD. It however remains unclear if these are genetically and/or phenotypically distinct disorders or just different spectrum of the same disease. We therefore explored the common genetic components underlying pediatric and adult CD in a well characterized north Indian cohort. Methods: A retrospective analysis of children (n = 531) and adult (n = 871) patients with CD between January 2001 and December 2010 was done. The database included basic demographic characteristics, clinical presentations, associated diseases and complications, if any. The genotype dataset was acquired for children (n = 217) and adult CD patients (n = 340) and controls (n = 736) using Immunochip. Association analysis was performed using logistic regression model to identify susceptibility genetic variants. Results: The predominant form of CD was classical CD in both pediatric and adult CD groups. There was remarkable similarity between pediatric and adult CD except for quantitative differences between the two groups such as female preponderance, non-classical presentation, co-occurrence of other autoimmune diseases being more common amongst adult CD. Notably, same HLA-DQ2 and -DQ8 haplotypes were established as the major risk factors in both types of CD. In addition, a few suggestively associated (p < 5 ? 10-4) non-HLA markers were identified of which only ANK3 (rs4948256-A; rs10994257-T) was found to be shared and explain risk for ?45 % of CD patients with HLA allele. Discussion: Overall phenotypic similarity between pediatric and adult CD groups can be explained by contribution of same HLA risk alleles. Different non-HLA genes/loci with minor risk seem to play crucial role in disease onset and extra intestinal manifestation of CD. None of the non-HLA risk variants reached genome-wide significance, however most of them were shown to have functional implication to disease pathogenesis. Functional relevance of our findings needs to be investigated to address clinical heterogeneity of CD. Conclusions: This present study is the first comparative study based on common genetic markers to suggest that CD in pediatric age group and in adults are the spectrum of the same disease with novel and shared genetic risk determinants. Follow-up fine mapping studies with larger study cohorts are warranted for further genetic investigation. ? 2016 The Author(s).Item PPARG and ADIPOQ gene polymorphisms increase type 2 diabetes mellitus risk in Asian Indian Sikhs: Pro12Ala still remains as the strongest predictor(2010) Sanghera, D.K.; Demirci, F.Y.; Been, L.; Ortega, L.; Ralhan, S.; Wander, G.S.; Mehra, N.K.; Singh, J.; Aston, C.E.; Mulvihill, J.J.; Kamboh, I.M.We have examined the association of 14 tagging single nucleotide polymorphisms (tagSNPs) in peroxisome proliferator activated receptor-? transcripts 1 and 2 (PPARG1 and 2) and 5 tagSNPs in adiponectin (ADIPOQ) genes for their effect on type 2 diabetes mellitus (T2D) risk in Asian Indian Sikhs. A total of 554 T2D cases and 527 normoglycemic controls were examined for association with T2D and other subphenotypes of T2D. With the exception of a strong association of PPARG2/Pro12Ala with T2D (odds ratio, 0.13; 95% confidence interval, 0.03-0.56; P = .0007), no other tagSNP in the PPARG locus revealed any significant association with T2D in this population. Similarly, none of the tagSNPs in the ADIPOQ gene was associated with T2D susceptibility in single-site analysis. However, haplotype analysis provided strong evidence of association of these loci with T2D. Three-site haplotype analysis in the PPARG locus using the 2 marginally associated SNPs (P/rs11715073 and P/rs3892175) in combination with Pro12 Ala (P/rs1801282) revealed a strong association of 1 "risk" (CGC) (P = .003, permutation P = .015) and 1 "protective" (CAC) (P = .001, permutation P = .005) haplotype associated with T2D. However, the major effect still appears to be driven by Pro12Ala, as the association of these haplotypes did not remain significant when analyzed conditional upon Pro12Ala (P = .262). In addition, 2-site haplotype analysis in the ADIPOQ locus using only 2 marginally associated SNPs (AD/rs182052 and AD/rs7649121) revealed a significant protective association of the GA haplotype with T2D (P = .009, permutation P = .026). Multiple linear regression analysis also revealed significant association of an ADIPOQ variant (AD/rs12495941) with total body weight (P = .010), waist (P = .024), and hip (P = .021), although these associations were not significant after adjusting for multiple testing. Our new findings strongly suggest that the genetic variation in PPARG and ADIPOQ loci could contribute to the risk for the development of T2D in Indian Sikhs. Identification of causal SNPs in these important biological and positional candidate genes would help determine the true physiologic significance of these loci in T2D and obesity. ? 2010 Elsevier Inc. All rights reserved.Item Genome-wide association study identifies a novel locus contributing to type 2 diabetes susceptibility in Sikhs of Punjabi origin from India(American Diabetes Association Inc., 2013) Saxena, R.; Saleheen, D.; Been, L.F.; Garavito, M.L.; Braun, T.; Bjonnes, A.; Young, R.; Ho, W.K.; Rasheed, A.; Frossard, P.; Sim, X.; Hassanali, N.; Radha, V.; Chidambaram, M.; Liju, S.; Rees, S.D.; Ng, D.P.-K.; Wong, T.-Y.; Yamauchi, T.; Hara, K.; Tanaka, Y.; Hirose, H.; McCarthy, M.I.; Morris, A.P.; Basit, A.; Barnett, A.H.; Katulanda, P.; Matthews, D.; Mohan, V.; Wander, G.S.; Singh, J.R.; Mehra, N.K.; Ralhan, S.; Kamboh, M.I.; Mulvihill, J.J.; Maegawa, H.; Tobe, K.; Maeda, S.; Cho, Y.S.; TaWe 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. ? 2013 by the American Diabetes Association.Item Genome-wide association studies in the Japanese population identify seven novel loci for type 2 diabetes(Nature Publishing Group, 2016) Imamura, M.; Takahashi, A.; Yamauchi, T.; Hara, K.; Yasuda, K.; Grarup, N.; Zhao, W.; Wang, X.; Huerta-Chagoya, A.; Hu, C.; Moon, S.; Long, J.; Kwak, S.H.; Rasheed, A.; Saxena, R.; Ma, R.C.W.; Okada, Y.; Iwata, M.; Hosoe, J.; Shojima, N.; Iwasaki, M.; Fujita, H.; Suzuki, K.; Danesh, J.; J?rgensen, T.; J?rgensen, M.E.; Witte, D.R.; Brandslund, I.; Christensen, C.; Hansen, T.; Mercader, J.M.; Flannick, J.; Moreno-Mac?as, H.; Burtt, N.P.; Zhang, R.; Kim, Y.J.; Zheng, W.; Singh, J.R.; Tam, C.H.T.; HGenome-wide association studies (GWAS) have identified more than 80 susceptibility loci for type 2 diabetes (T2D), but most of its heritability still remains to be elucidated. In this study, we conducted a meta-analysis of GWAS for T2D in the Japanese population. Combined data from discovery and subsequent validation analyses (23,399 T2D cases and 31,722 controls) identify 7 new loci with genome-wide significance (P<5 ? 10-8), rs1116357 near CCDC85A, rs147538848 in FAM60A, rs1575972 near DMRTA1, rs9309245 near ASB3, rs67156297 near ATP8B2, rs7107784 near MIR4686 and rs67839313 near INAFM2. Of these, the association of 4 loci with T2D is replicated in multi-ethnic populations other than Japanese (up to 65,936 T2Ds and 158,030 controls, P<0.007). These results indicate that expansion of single ethnic GWAS is still useful to identify novel susceptibility loci to complex traits not only for ethnicity-specific loci but also for common loci across different ethnicities. ? 2016, Nature Publishing Group. All rights reserved.Item Association of GABRA6 1519 T>C (rs3219151) and Synapsin II (rs37733634) gene polymorphisms with the development of idiopathic generalized epilepsy(Elsevier, 2014) Prasad, D.K.V.; Shaheen, U.; Satyanarayana, U.; Prabha, T.S.; Jyothy, A.; Munshi, A.The idiopathic generalized epilepsy (IGE) is a neurological disorder which accounts for approximately 30% of all epilepsy cases. Patients identified with IGE syndromes have pharmacoresponsive epilepsies without abnormal neurological symptoms, structural brain lesions and are of unknown origin. A genetic etiology to IGEs has been proposed. Gamma amino butyric acid (GABA), a major inhibitory neurotransmitter acts by binding to transmembrane GABAA and GABAB receptors of both pre- and postsynaptic neurons. Synapsin II (SynII), a neuron specific phosphoprotein plays a major role in synaptogenesis and neurotransmitter release. The present study was carried out with an aim to evaluate the association of GABRA6 (rs3219151) T>C and Syn II (rs37733634) A>G gene polymorphisms with IGE. Molecular analysis revealed that the frequency of 'CC' genotype and 'C'allele of GABRA6 (rs3219151) T>C gene polymorphism was significantly higher in IGE patients compared to healthy controls [CC vs. TT, ?2=26; p<0.001; Odds ratio=3.6 (95% CI; 2.1-5.9); C vs T, ?2=24.7; p<0.001; Odds ratio=1.78 (95% CI; 1.4-2.2)]. The frequency of 'GG' genotype and 'G' allele of the intronic polymorphism A>G in Syn II gene was also found to be significantly associated with the disease when compared to controls [GG vs AA, ?2=64.52; p<0.001; Odds ratio=7.37 (95% CI; 4.4-12.3); G vs. A, ?2=65.78; p<0.001; Odds ratio=2.57 (95% CI; 2.0-3.2)]. The generalized multifactor dimensionality reduction method was employed to detect gene-gene interactions. The gene-gene interaction at two loci involving GABRA6 and Syn II revealed a significant association [?2=36.6, p<0.001, Odds ratio=3.17 (95% CI; 2.2-4.6)] with IGE. Therefore, the present study clearly indicates that both GABRA6 (rs3219151) T>C and Syn II (rs37733634) A>G polymorphisms are important risk factors for the development of IGE in the South Indian population from Andhra Pradesh. The gene-gene interaction studies demonstrated significant interactive effects of these two loci in the development of the disease. ? 2014 Elsevier B.V.Item A low frequency variant within the GWAS locus of MTNR1B affects fasting glucose concentrations: Genetic risk is modulated by obesity(2012) Been, L.F.; Hatfield, J.L.; Shankar, A.; Aston, C.E.; Ralhan, S.; Wander, G.S.; Mehra, N.K.; Singh, J.R.; Mulvihill, J.J.; Sanghera, D.K.Two common variants (rs1387153, rs10830963) in MTNR1B have been reported to have independent effects on fasting blood glucose (FBG) levels with increased risk to type 2 diabetes (T2D) in recent genome-wide association studies (GWAS). In this investigation, we report the association of these two variants, and an additional variant (rs1374645) within the GWAS locus of MTNR1B with FBG, 2h glucose, insulin resistance (HOMA IR), ?-cell function (HOMA B), and T2D in our sample of Asian Sikhs from India. Our cohort comprised 2222 subjects [1201 T2D, 1021 controls]. None of these SNPs was associated with T2D in this cohort. Our data also could not confirm association of rs1387153 and rs10830963 with FBG phenotype. However, upon stratifying data according to body mass index (BMI) (low ? 25 kg/m2 and high > 25 kg/m2) in normoglycemic subjects (n = 1021), the rs1374645 revealed a strong association with low FBG levels in low BMI group (? = -0.073, p = 0.002, Bonferroni p = 0.01) compared to the high BMI group (? = 0.015, p = 0.50). We also detected a strong evidence of interaction between rs1374645 and BMI with respect to FBG levels (p = 0.002). Our data provide new information about the significant impact of another MTNR1B variant on FBG levels that appears to be modulated by BMI. Future confirmation on independent datasets and functional studies will be required to define the role of this variant in fasting glucose variation. ? 2011.Item A novel 7 bp deletion in PRPF31 associated with autosomal dominant retinitis pigmentosa with incomplete penetrance in an Indian family(2012) Saini, S.; Robinson, P.N.; Singh, J.R.; Vanita, V.To localize and identify the gene linked with non-syndromic autosomal dominant retinitis pigmentosa (adRP) with high but not complete penetrance in an Indian family. A detailed family history and clinical data were recorded. A genome-wide scan by 2-point linkage analysis using nearly 400 fluorescently labeled microsatellite markers in combination with multipoint lod score and haplotype analysis was carried out. Mutation screening was performed in the candidate gene by bidirectional sequence analysis of the amplified products. A maximum 2-point lod score of 3.553 at theta = 0.0 was obtained with marker D19S572. Haplotype analysis placed the RP locus distal to marker D19S572, in close proximity to the gene for pre-mRNA processing factor 31 (PRPF31) at 19q13.42. Mutation screening in all 14 exonic regions and adjacent flanking intronic sequences of PRPF31 revealed a novel 7 bp deletion, c.59_65del7 (p.Gly20AlafsX43), in the first coding exon of PRPF31. This leads to a premature termination codon (PTC) in the next exon, 43 amino acids downstream. The observed 7 bp deletion in PRPF31 was identified in all the tested 10 affected members and in an unaffected individual, consistent with a high, but not the complete penetrance of c.59_65del7 (p.Gly20AlafsX43). This deletion was not observed in other tested six unaffected family members or in 100 ethnically matched control subjects. The present study describes mapping of a locus for non-syndromic adRP at 19q13.42 (RP11 locus) in a family of Indian origin and identifies a novel deletion, c.59_65del7, in PRPF31 within the mapped interval. Since the mutant PRPF31 is truncated relatively close to the N-terminus of the protein, haploinsufficiency rather than aberrant protein formation is likely to be the underlying mechanism of the disease. The present findings further substantiate the role of PRPF31 that encodes a component of the spliceosome complex in relation to ADRP. ? 2012 Elsevier Ltd.