Alcohol dependence is a common, highly familial disorder that is a leading cause of morbidity and premature death. It results in serious medical, legal, social and psychiatric problems and influences many facets of American society. It affects 4 to 5% of the United States population at any given time, with a lifetime prevalence of 12.5% [1], [2]. Family, twin and adoption studies have demonstrated that genetic factors constitute a significant cause for alcohol dependence. A large number of risk loci have been reported for alcohol dependence (AD) by candidate gene approach. Several genome-wide association studies (GWASs) [3], [4], [5], [6], [7] have also reported tens of risk loci for alcohol dependence and alcohol consumption (summarized by Zuo et al. [3]). However, most GWAS findings have not been replicated in independent samples and confirmed by functional studies.
