Given the sample size, it was not feasible to include the less frequently available GG genotype as a separate group. In that regard it should be noted that there are data linking the G allele of rs279871 to increased risk of alcoholism (e.g., Fehr, et al., 2006). Therefore, secondary analyses were performed, adding these four GG subjects to the AG group. This resulted in the left vmPFC changing from p< 0.05 to p< 0.06, and the left mPFC and right vmPFC genotype differences remaining significant. Future research including more GG subjects is needed to better understand the relationship between this genotype and phenotype.
