Given that twin studies have shown that inherited factors account for 40% to 60% of the variance in alcohol sensitivity (Heath et al., 1999), and under the hypothesis that the same genes that predict increased risk for alcoholism may also mediate a distinctive response to alcohol, studies have begun to examine the association of subjective responses to alcohol with variants in GABRA2. In one such study, individuals homozygous for the more common allele of a GABRA2 single SNP (rs279858) reported greater subjective effects of alcohol than individuals with 1 or 2 copies of the AD-associated minor allele (Pierucci-Lagha et al., 2005). However, this study examined only a single SNP. More recently, in a study that used the alcohol clamp method for intravenous (i.v.) alcohol administration, subjects with the more common allele in 3 SNPs located in the middle of GABRA2 showed greater subjective responses to alcohol than individuals homozygous for the AD-associated minor alleles (Roh et al., 2010).
