An alcohol dependent case and non-alcohol dependent control series of unrelated individuals was selected from more than 10,000 subjects who participated in the genetic arm of COGA. COGA systematically recruited families with multiple members affected with alcohol dependence and community-based comparison families from participating centers across the United States. From this larger sample, a subset of unrelated alcohol dependent individuals was selected for genotyping. (11). Control subjects, who used alcohol but never met criteria for alcohol or drug dependence, were selected for genotyping. Because this study focused on alcohol dependence, nicotine dependence was not an exclusionary criterion for the control subjects. The present study includes 1403 unrelated, genotyped subjects from COGA.
