DNA was obtained from blood samples and genotyping was carried out at the Johns Hopkins University Center for Inherited Disease Research (CIDR) using the Illumina Human IM Bead Chip. The median missing call rate was less than 0.05%, with 95% of SNPs resulting in less than 1.4% missingness. Strict quality control procedures were implemented, including assessment of population structure, missing call rates, Mendelian errors, duplication errors, gender and chromosomal anomalies, hidden relatedness, batch effects, and Hardy-Weinberg disequilibrium. Duplicates, related subjects, and outliers were removed. A total of 948,142 SNPs passed this thorough cleaning procedure (Laurie et al., under review; http://www.genevastudy.org/).
