These identified limitations are balanced by study strengths. The selection of a GABRA2-SNP variant for inclusion in our model was based on an extensive literature review that suggested this gene's association with a wide range of alcohol-related problems, including a relationship with externalizing behavior, a known precursor of both drinking initiation and alcohol-use problems. Furthermore, two recent studies (Demers, Bogdan, & Agrawal, 2014; Villafuerte, Strumba, Stoltenberg, Zucker, & Burmeister, 2013) suggest that the association of GABRA2 SNPs (including rs279871) with alcohol-related phenotypes may be mediated by impulsivity, which is itself related to externalizing behavior (Eisenberg et al., 2009). Within GABRA2, the rs279871 SNP was selected because in the COGA sample it is in high linkage disequilibrium with other SNPs associated with alcohol dependence in adults, and therefore represents most of the relevant genetic variability within this gene. Our finding that the major allele (T) is the risk allele is at odds with the two meta-analyses cited above; however, the relative frequencies of the major and minor alleles in our study were not significantly different in the overall sample or the
