Several genome-wide association analysis (GWAS) have been carried out to find genes that contribute to risk for AD (Bierut et al. 2010; Edenberg et al. 2010; Kendler et al. 2011; Treutlein et al. 2009; Wang et al. 2012a), and alcohol consumption (Baik et al. 2011; Heath et al. 2011; Schumann et al. 2011). Recently, Schumann and colleagues (Schumann et al. 2011) performed a meta-analysis using 12 population-based GWAS and reported genome-wide association of a SNP in the autism susceptibility candidate 2 gene (AUTS2) with alcohol consumption (grams per day per kilogram body weight). In another GWAS, Baik and colleagues (Baik et al. 2011) identified twelve SNPs on chromosome 12 that were strongly associated with alcohol consumption (grams per day) in Korean men. A GWAS of a quantitative factor score created from indices of excessive alcohol consumption that included maximum number of alcoholic drinks consumed in 24 hours (maxdrinks), reported many variants approaching the genome-wide threshold for suggestive significance (p < 5 × 10−5) (Heath et al. 2011). Bierut and coworkers (2012) used maxdrinks as a standalone measure of alcohol consumption
