Recent success in the discovery of coronary artery disease genes

For more than 50 years, epidemiological studies have indicated that genetic predisposition accounts for approximately 50% of the susceptibility to coronary artery disease (CAD) and its sequelae, including myocardial infarction. Since common diseases such as CAD are caused by multiple genes, the age-old method of linkage analysis used to map monogenic Mendelian disorders in families unfortunately lacks the required sensitivity. The technology to identify genes predisposing individuals to CAD and other common diseases did not become available until 2005. This technology provided computerized arrays containing hundreds of thousands of DNA markers in the form of single-nucleotide polymorphisms (SNPs). This made it possible to pursue an unbiased approach referred to as genome-wide association studies. The first gene for CAD was simultaneously identified by 2 independent groups in 2007. In a very short interval, a total of 23 loci were mapped that were linked to increased risk for CAD. The results of these studies confirm that CAD is caused by multiple genes, each contributing minimal risk. The most exciting and novel findings are that these loci do not act through known risk factors for CAD and that the loci are more likely to be in DNA regions that regulate transcription rather than being in coding regions for protein.