The SNP rs7865618 of 9p21.3 locus emerges as the most promising marker of coronary artery disease in the southern Indian population.

Development of coronary artery disease (CAD) is primarily due to the process of atherosclerosis, however the prognosis of CAD depends on pleiotropic effects of the genes located at 9p21.3 region. Genome wide association studies revealed association of variants in this region with CAD pathology. However, specific marker in predicting CAD development or progression is not yet identified. In the present study, 35 SNPs at 9p21.3 region, located in the cyclin dependent kinase inhibitor (CDKN2A/CDKN2B) genes, were genotyped among 350 CAD cases and 480 controls from the southern Indian population of Hyderabad using fluidigm nanofluidic SNP genotyping system and the data were analyzed using PLINK and R softwares. Of the 35 SNPs analysed, only one SNP, rs7865618, was found to be highly significantly associated with CAD, even after correction for multiple testing (p = 0.008). The AG and GG genotypes of this SNP conferred 3.08 and 1.93 folds increased risk for CAD respectively. In particular, this SNP was significantly associated with severe anatomic (triple vessel disease p = 0.023) and phenotypic (acute coronary syndrome p = 0.007) categories of CAD. Pair wise SNP interaction analysis between the SNPs of 9p21.3 and 11q23.3 regions revealed significantly increased risk of three SNPs of 11q23.3 region that were not associated individually, in conjunction with rs7865618 of 9p21.3.

Overview of genomics and post-genomics research on type 2 diabetes mellitus: Future perspectives and a framework for further studies.

In this review, we briefly outlined salient features of pathophysiology and results of the genetic association studies hitherto conducted on type 2 diabetes. Primarily focusing on the current status of genomic research, we briefly discussed the limited progress made during the post-genomic era and tried to identify the limitations of the post-genomic research strategies. We suggested reanalysis of the existing genomic data through advanced statistical and computational methods and recommended integrated genomics-metabolomics approaches for future studies to facilitate understanding of the gene-environment interactions in the manifestation of the disease. We also propose a framework for research that may be apt for determining the effects of urbanization and changing lifestyles in the manifestation of complex genetic disorders like type 2 diabetes in the Indian populations and offset the confounding effects of both genetic and environmental factors in the natural way.

Quantitative trait loci at the 11q23.3 chromosomal region related to dyslipidemia in the population of Andhra Pradesh, India.

BACKGROUND: Given the characteristic atherogenic dyslipidemia of south Indian population and crucial role of APOA1, APOC3, APOA4 and APOA5 genes clustered in 11q23.3 chromosomal region in regulating lipoprotein metabolism and cholesterol homeostasis, a large number of recently identified variants are to be explored for their role in regulating the serum lipid parameters among south Indians. METHODS: Using fluidigm SNP genotyping platform, a prioritized set of 96 SNPs of the 11q23.3 chromosomal region were genotyped on 516 individuals from Hyderabad, India, and its vicinity and aged >45 years. RESULTS: The linear regression analysis of the individual lipid traits viz., TC, LDLC, HDLC, VLDL and TG with each of the 78 SNPs that confirm to HWE and with minor allele frequency > 1%, suggests 23 of those to be significantly associated (p ≤ 0.05) with at least one of these quantitative traits. Most importantly, the variant rs632153 is involved in elevating TC, LDLC, TG and VLDLs and probably playing a crucial role in the manifestation of dyslipidemia. Additionally, another three SNPs rs633389, rs2187126 and rs1263163 are found risk conferring to dyslipidemia by elevating LDLC and TC levels in the present population. Further, the ROC (receiver operating curve) analysis for the risk scores and dyslipidemia status yielded a significant area under curve (AUC) = 0.675, suggesting high discriminative power of the risk variants towards the condition. The interaction analysis suggests rs10488699-rs2187126 pair of the BUD13 gene to confer significant risk (Interaction odds ratio = 14.38, P = 7.17 × 105) towards dyslipidemia by elevating the TC levels (ß = 37.13, p = 6.614 × 105). On the other hand, the interaction between variants of APOA1 gene and BUD13 and/or ZPR1 regulatory genes at this region are associated with elevated TG and VLDL. CONCLUSION: The variants at 11q23.3 chromosomal region seem to determine the quantitative lipid traits and in turn dyslipidemia in the population of Hyderabad. Particularly, the variants rs632153, rs633389, rs2187126 and rs1263163 might be risk conferring to dyslipidemia by elevating LDLC and TC levels, while the variants of APOC3 and APOA1 genes might be the genetic determinants of elevated triglycerides in the present population.

Genetic determinants of clinical heterogeneity of the coronary artery disease in the population of Hyderabad, India.

BACKGROUND: Genetic predisposition to the clinical categories of coronary artery disease (anatomical viz., insignificant, single, double, and triple vessel diseases and phenotypic severity categories viz., angina, acute coronary syndrome, and myocardial infarction) is poorly understood. Particularly, the apolipoprotein genes clustered at 11q23.3 chromosomal region play a vital role in cholesterol homeostasis, and a large number of SNPs identified in this region need to be explored for their association with the clinical categories of CAD. METHODS: Using fluidigm SNP genotyping platform, a prioritized set of 96 SNPs of 11q23.3 chromosomal region were genotyped on 508 CAD cases and 516 ethnicity matched controls, enrolled from Hyderabad, India, and its vicinity. RESULTS: The association analysis suggests 19 and 15 SNPs to be significantly associated (p ≤ 0.05) with at least one of the anatomical and/or phenotypic severity categories, respectively. Overall, the six SNPs rs17440396:G>A, rs6589566:A>G, rs2849165:G>A, rs10488699:G>A, rs1263163:G>A, and rs1263171:G>A were significant even after correction for multiple testing. Three of these (rs17440396:G>A, rs6589566:A>G, and rs2849165:G>A) that belong to BUD13, ZPR1, and APOA5-APOA4 intergenic regions, respectively, were found to be associated across the anatomical categories of CAD. However, no particular trend in the genotypic odds ratios with the increasing severity was apparent. The association analysis of the variants with phenotypic severity categories suggests that a high degree of phenotypic severity could be a result of more number of risk alleles. While the risk score analysis suggests high discriminative power of the variants towards the individual clinical categories of CAD, the complex network of interactions seen between the intronic variants of BUD13 and ZPR1 regulatory genes and intergenic variants of APOA5-APOA4 suggests pleiotropic effects of regulatory genes in the manifestation of these CAD categories. CONCLUSION: The complex network of interactions observed in the present study between the regulatory and protein-coding genes suggests their role in the manifestation of distinct clinical categories of CAD, which needs to be functionally validated.