In COGA, participants were genotyped on four different genotyping arrays: the Illumina 1M, Illumina OmniExpress 12VI, and Illumina 2.5M (Illumina, San Diego, CA), and Smokescreen (BioRealm LLC, Walnut, CA); details of genotyping, imputation and quality control procedures are available in Lai et al. (2019) and Johnson et al. (in press). In ALSPAC, participants were genotyped on the Illumina Human Hap550 Quad array. Additional information regarding genotyping procedures in ALSPAC is available in Paternoster et al. (2011) and Chong et al. (2021). In Add Health, participants were genotyped on the Illumina Human Omni1-Quad BeadChip and the Illumina Human Omni-2.5 Quad BeadChip. Genotypes in Add Health were imputed together using a set of 609,130 SNPs in common between the two arrays. Additional information regarding genotyping procedures in Add Health is available in Highland et al. (2018).
