For each candidate gene, all SNPs with p<.05 were queried together in SNP Annotation and Proxy Search (SNAP) to assess linkage disequilibrium (Johnson et al., 2008). These searches were performed using the 1000 genomes pilot 1 SNP dataset, an r2 ≥ .8, and a distance limit of 500. This analysis was performed with both the CEU and YPI population panels separately because of allele frequency differences between European American and African American subsets. All SNPs that had an r2 greater than 0.8 and at least one other variant in a group were considered a cluster.
