A sub-sample of COGA families was selected to maximize the contribution of genetic variants to the risk for AD. All families recruited by COGA were reviewed and prioritized based on, in preferential order: 1) the largest number of AD family members with DNA; 2) the largest number of family members with electrophysiology data and DNA; and 3) the largest number of family members with DNA regardless of other phenotypes. The final sample consisted of 118 large, multiplex European American families, with DNA available from 2,322 individuals.
