Expanding Discovery in Cardiovascular Genome-Wide Association Studies

Abstract

For nearly 15 years, genome-wide association studies (GWASs) have yielded many new insights into cardiovascular disease. These studies have disproportionately evaluated European and, to a lesser extent, Asian cohorts, limiting discovery opportunities. Genome-wide association studies of individuals of African ancestry typically living in the US are uncommon, yet they have yielded high-impact observations, including the discovery that PCSK9 loss-of-function mutations protect against coronary artery disease. 1 Genome-wide association studies of individuals living in Africa are even rarer, representing approximately 0.4% of GWAS participants. 2 In this issue of JAMA Cardiology, Machipisa and colleagues 3 describe a GWAS of rheumatic heart disease (RHD) in Africa, where the prevalence of RHD is 10-fold greater than in North America and Western Europe. This study found an association between an important chronic disease and genetic susceptibility loci in African individuals, provides ancestry-based disease associations, and emphasizes the need for a more robust genetic architecture to promote future genetic discovery.The RHD study included 2548 cases and 2261 controls from multiple sites throughout Africa. 3 The authors identified a genomic signal with a population frequency of 9% at chromosome 11q24.1, which was associated with 1.63-fold odds for RHD. As in most GWASs, the identified variants occurred in non-protein-coding regions of the genome. Normally, external data sets in which non-protein-coding variation have been mapped to genes are leveraged to glean mechanistic insights.