No abstract

The most frequent causes of death and disability in the Western world are atherosclerotic coronary artery disease (CAD) and acute myocardial infarction (MI). This common disease is thought to have a polygenic basis with a complex interaction with environmental factors. Here, we report results of a genomewide search for susceptibility genes for MI in a well-characterized U.S. cohort consisting of 1,613 individuals in 428 multiplex families with familial premature CAD and MI: 712 with MI, 974 with CAD, and average age of onset of 44.4+/-9.7 years. Genotyping was performed at the National Heart, Lung, and Blood Institute Mammalian Genotyping Facility through use of 408 markers that span the entire human genome every 10 cM. Linkage analysis was performed with the modified Haseman-Elston regression model through use of the SIBPAL program. Three genomewide scans were conducted: single-point, multipoint, and multipoint performed on of white pedigrees only (92% of the cohort). One novel significant susceptibility locus was detected for MI on chromosomal region 1p34-36, with a multipoint allele-sharing P value of <10(-12) (LOD=11.68). Validation by use of a permutation test yielded a pointwise empirical P value of.00011 at this locus, which corresponds to a genomewide significance of P<.05. For the less restrictive phenotype of CAD, no genetic locus was detected, suggesting that CAD and MI may not share all susceptibility genes. The present study thus identifies a novel genetic-susceptibility locus for MI and provides a framework for the ultimate cloning of a gene for the complex disease MI.

Objective— Recent genome-wide association studies have identified 4 SNPs on chromosome 9p21 associated with CAD (rs10757274 and rs2383206) and myocardial infarction (MI: rs2383207 and rs10757278) in White populations in Northern Europe and North America. We aimed to determine whether this locus confers significant susceptibility to CAD in a South Korean population, and thus cross-race susceptibility to CAD. Methods and Results— We performed a case-control association study with 611 unrelated CAD patients and 294 normal controls from South Korea. Allelic associations of SNPs and SNP haplotypes with CAD were evaluated. Multivariate logistic regression analysis was used to adjust effects of clinical covariates. We found that 4 SNPs on chromosome 9p21 were associated with susceptibility to CAD in a South Korean population. The association remained significant after adjusting for significant clinical covariates ( P =0.001 to 0.024). We identified one risk haplotype (GGGG; P =0.017) and one protective haplotype (AAAA; P =0.007) for development of CAD. Further analysis suggested that the SNPs probably confer susceptibility to CAD in a dominance model (covariates-adjusted P =0.001 to 0.024; OR=2.37 to 1.54). This represents the first study that expands association of these 9p21 SNPs with CAD beyond White populations. Conclusion— Chromosome 9p21 is an important susceptibility locus that confers high cross-race risk for development of CAD.