The Collaborative Study on the Genetics of Alcoholism (COGA) Case Control Study is a case-control GWA study of AD. It contains about 1 million Illumina SNPs (1,069,796 SNPs), and 1234 cases with AD and 711 controls (Edenberg et al., 2010). Phenotypes include AD as a binary trait according to DSM-IV diagnosis. Besides, another quantitative and heritable phenotype MaxDrinks that measured the maximum number of drinks a person has consumed in a 24-hour period has been included in the study which increased the study power (Edenberg et al. 2002). In the present study, we chose 1059 Caucasian (non-Hispanic) individuals (572 males and 487 females) with MaxDrinks.
