Samples from the COGA DNA and Cell Repository at Rutgers University were genotyped at the Genome Technology Access Center at Washington University School of Medicine in St. Louis using the Illumina Human OmniExpress array 12.VI (731,444 SNPs; Illumina, San Diego, CA, USA) on 2098 subjects selected from 118 densely affected families. An additional 224 subjects from these 118 families had been genotyped in a previous case-control GWAS by the Center for Inherited Disease Research (CIDR) at John Hopkins University using the Illumina Human 1M-Duo BeadChip technology (1,041,465 SNPs; Illumina, San Diego, CA, USA; Edenberg et al. 2010). To insure quality control, 51 subjects previously genotyped at CIDR were included among the 2098 subjects genotyped at Washington University.
