ADH1B genotypes were obtained from the MVP GWAS, which used a custom Affymetrix Axiom Biobank Array, with 686,693 markers. The custom array is enriched for exomic SNPs, has SNPs validated for medical and psychiatric traits, and was augmented with biomarkers of specific interest to the VA population—including enrichment for African-American and Hispanic ancestry markers and validated markers for common diseases (9). The standardized Affymetrix best practice workflow was used to produce genotype data (19). Both rs2066702 and rs1229984 were directly genotyped on the array. For rs2066702 (Arg369Cys), the major (C) allele encodes an arginine and the minor (T) allele encodes a cysteine. For rs1229984 (Arg48His), the major (G) allele encodes an arginine and the minor (A) allele encodes a histidine. The genotype distribution for rs1229984 in EAs was consistent with Hardy-Weinberg Equilibrium expectations (HWEE) (χ2 (1) = 2.04, p=0.15) after exclusion of a subpopulation with a high MAF that was identified as outlying on principal components (PC) analysis. In AAs, there was no significant departure from HWEE considering the large sample size (χ2 (1) = 4.21, p=0.04).
