All genotyping was performed by the Center for Inherited Disease Research (CIDR). The COGA and FSCD samples were genotyped using Illumina Human1Mv1_C BeadChips. COGEND subjects were genotyped using two genome-wide SNP arrays: Illumina Human1Mv1_C and Illumina HumanOmni2.5M. Extensive cleaning was undertaken to ensure high-quality genotyping by examining batch effects, call rates, and other quality metrics (11).
