Haplotypes on 9p21 modify the risk for coronary artery disease among Indians

The chromosomal region 9p21 has been reported to be associated with myocardial infarction, coronary artery disease (CAD), diabetes, and many other related multifactorial diseases in humans. Although the genome-wide association studies have identified a limited number of single-nucleotide polymorphisms (SNPs) at 9p21 for CAD risk, the role of flanking SNPs has not been studied so far. Therefore, in the present work, we studied the role of flanking SNPs with respect to that of the previously identified SNPs rs10757278 and rs2383207 at 9p21 among the Indian subjects found to have CAD (n = 414) along with age- and sex-matched control subjects (n = 408). Our study replicated the association of genome-wide association studies that had identified SNPs rs2383207 (p = 4.7 × 10(-5)) and rs10757278 (p = 5.5 × 10(-5)) among Indians with CAD. Further, we evaluated nine additional SNPs, of which two SNPs flanking rs2383207 (rs1537375 [p = 2.4 × 10(-5)] and rs1537374 [p = 5.6 × 10(-5)]) were also strongly associated with CAD. The haplotypes constructed using four risk SNPs revealed that the haplotypes with combinations of rs10757278 showed CAD risks, whereas the minor alleles of rs2383207, rs1537375, and rs1537374 in combinations reduce the CAD risks substantially. Our study demonstrates that the variation in the chromosomal region 9p21 is involved in modifying progression toward CAD among Indians and the risk may be variable, contributed by the SNPs that are flanking previously identified SNPs.