Although genotypic differences at SNPs in the GABRA2 gene are correlated with differences in subjective responses to alcohol, the functional effects of the allelic variation at GABRA2 are not understood (Covault et al., 2004; Dick et al., 2006; Edenberg et al., 2004; Lappalainen et al., 2005; Soyka et al., 2008). To our knowledge, no common functional coding sequence variants have been described in the GABRA2 gene. The SNPs 4 and 6 are located in introns 6 and 3 of GABRA2, respectively; thus, we know that these are not coding SNPs. The SNP5 is located in exon 5 of GABRA2, but this type of SNP is known as a silent mutation. There are no additional data on possible functions of these SNPs. It is unclear whether these particular SNPs are directly involved in the subjective responses to alcohol or whether the SNPs are in linkage disequilibrium with the actual variant in GABRA2 that causes differences in the alcohol effects. Therefore, additional research is required to elucidate the potential mechanism by which the gene influences the subjective responses to alcohol.
