Because both GWAS samples had the same SNPs genotyped, and were confirmed to share the direction of the genotyped strand, GWAS results were matched directly by allele. Genetic sum scores were created for autosomal SNPs composed of the total number of minor alleles for each SNP carried by each individual, so that homozygotes for the risk allele had a score of 2. Each SNP allele count was weighted by the natural log of the odds ratio for each minor allele, and then the sum of the weighted allele count was divided by the number of non-missing genotypes for each individual using PLINK v1.07. The p-values associated with the AUCs for these sum scores were calculated based on the Wilcoxon rank-sum test using R v2.12.2.
