Four different genome-wide genotyping arrays were used in COGA: 1. COGA case/control data were genotyped on the Illumina Human1M array (Illumina, San Diego, CA, USA) at the Center for Inherited Disease Research (CIDR), Johns Hopkins University 7; 2. COGA European American family data were genotyped on the Illumina Human OmniExpress 12V1 array (Illumina, San Diego, CA, USA) at the Genome Technology Access Center, Washington University School of Medicine 9,34; 3. COGA AA family data were genotyped on the Illumina 2.5M array (Illumina, San Diego, CA, USA) at CIDR 35; 4. The remaining samples were genotyped on the Smokescreen genotyping array (Biorealm LLC, Walnut, CA, USA) at Rutgers University. Among these arrays, two to 127 samples were genotyped on at least two different arrays with pairwise concordance rates all > 99.18%.
