Association between four SNPs on chromosome 9p21 and myocardial infarction is replicated in an Italian population

Genome-wide single nucleotide polymorphism (SNP) association studies recently identified four SNPs (rs10757274, rs2383206, rs2383207, and rs10757278) on chromosome 9p21 that were associated with coronary artery disease (CAD) and myocardial infarction (MI) in Caucasian populations from northern Europe and North America. Our aim was to determine whether these SNPs were associated with MI in a southern Europe/Mediterranean population. We employed a case-control association design involving 416 MI patients and 308 non-MI controls from Italy. Significant allelic association was identified between all four SNPs and MI. The association remained significant after adjusting for covariates for MI (P=0.007-0.029). One risk haplotype (GGGG; P=0.028) and one protective haplotype (AAAA; P=0.047) were identified. Genotypic association analysis demonstrated that the SNPs conferred susceptibility to MI most likely in a dominant model (P=0.0007-0.013). When the case cohort was divided into a group of MI patients with a family history (n=248) and one group without it (n=168), the positive, significant association was identified only in the group with the family history. These results indicate that chromosome 9p21 confers risk for development of MI in an Italian population.