GWAS has greatly increased our understanding of the genetic etiology of AD. The most robust associations for AD have been with the alcohol metabolizing enzyme genes, especially ALDH2 in East Asian populations (Park et al., 2013; Quillen et al., 2014), and ADH1B in European-American and African-American populations (Frank et al., 2012; Gelernter et al., 2014a). Samples in the tens of thousands will likely be necessary to detect additional loci beyond those identified by the best-powered AD GWAS to date (Gelernter et al. 2014a).
