over-represented among alcoholics (Covault et al., 2004; Fehr et al., 2006; Lappalainen et al., 2005). In each of these studies the frequency of the G-allele ranged from 34 to 42% in the control samples - a frequency similar to that observed in our population. The G-allele has also been associated with an increased probability of daily drinking and heavy drinking during 12-week treatment and 12-month post-treatment periods in alcoholics participating in the Project MATCH study (Bauer et al., 2007). Recently, Haughey and colleagues (2008) found that prefrontal cortex (PFC) GABRA2 mRNA levels in postmortem brains and an individual's sensitivity to the acute affects of alcohol were significantly influenced by the GABRA2 rs279858 SNP genotype. Heterozygous individuals exhibited less reward from alcohol than either homozygote, and postmortem brains of A/G individuals had significantly lower PFC mRNA levels compared to A/A homozygotes, suggesting that the A/G genotype may protect against developing alcohol dependence.
