Genetic variants of chromosome 9p21.3 region associated with coronary artery disease and premature coronary artery disease in an Asian Indian population.

INTRODUCTION: Asian Indians have a propensity for premature, severe, and diffuse coronary artery disease (CAD). Several single-nucleotide polymorphisms (SNPs) in the 'core CAD' region of the chromosomal region 9p21.3 are known to be strongly associated with CAD. OBJECTIVES: We aimed to study SNPs in the 9p21.3 region associated with CAD and premature CAD and identify their association with demographic and clinical characteristics in an Asian Indian population. METHODS: SNP genotyping was performed for 30 SNPs of the 9p21.3 region using MassARRAY® technology. Along with demographic and SNP data analysis, we also performed multivariate logistic regression analysis and multifactor dimensionality reduction analysis to study SNP-SNP and SNP-demographic/clinical variable interactions. RESULTS: Our results suggest that females are at a higher risk of premature CAD. We found that SNPs rs1333045 (CC), rs16905599 (AA), rs2383206 (GG), rs2383208 (AG), and rs4977574 (GG) were significantly associated with premature CAD. When adjusted for covariates/confounders, we found that rs2383206 showed the strongest risk association with CAD followed by rs16905599 and rs2383208. Further, SNPs rs1333049 (CC) and rs4977574 (GG) were found to be exclusively associated with premature CAD cases, suggesting their potential as genetic markers for premature CAD in the local population. Upon gender-based stratification, it was found that rs10757272 (TT and TC) is significantly associated with eightfold to ninefold CAD risk specifically among females. SNP rs7865618 (GG) is significantly associated with more than 2.5-fold CAD risk specifically among males. CONCLUSION: Our study suggests that SNPs at the 9p21 risk locus may be used to generate a reliable genetic risk score along with markers at other loci.

9p21.3 coronary artery disease risk locus and interferon alpha 21: Association study in an Asian Indian population.

INTRODUCTION: Type I Interferons (INFαs and INF ß) are known to be proinflammatory cytokines that promote atherosclerosis. IFNA21 is a member of alpha Interferon gene cluster on short arm of chromosome 9. We analyzed the potential link between 9p21 coronary artery disease (CAD) risk locus and IFNA21. OBJECTIVES: a) study of association between serum IFNA21 levels and 14 demographic/clinical variables, including age, gender, diabetes, hypertension, and duration of CAD, b) study of association between high serum IFNA21 levels and 30 9p21 SNP genotypes. METHODS: To estimate serum circulating levels of IFNA21, we performed sandwich ELISA in 184 controls and 167 CAD cases. The IFNA21 levels could be classified into two broad classes: a) Low-level group: ≤15.6 pg/ml b) High-level group: >15.6 pg/ml. We also performed SNP genotyping for 30 SNPs at 9p21 locus in all study subjects using Sequenom MassARRAY technology. Statistical software SPSS (Version 21) was used to analyze the data obtained. RESULTS: Our analysis indicates that there could be an association of high IFNA21 levels with variables - gender, age, and duration of CAD in the study population. SNPs rs10757272 (TT), rs10757274 (GG), rs10757283 (TT), rs1333045 (CC), rs1333048 (CC), rs1333049 (CC), and rs4977574 (GG) showed significant risk association with high-level IFNA21 group. CONCLUSIONS: IFNA21 may be involved in inflammatory processes in an age-dependent manner and in progression of CAD. This IFNA21-mediated mechanism may be more active in females. Several 9p21 SNPs may modulate inflammatory processes mediated by IFNA21 and may, therefore, contribute to pathophysiology of CAD.