Edenberg et al (2004) genotyped six GABRG1 SNPs in the family-based COGA dataset extending from the 5′ region to intron 8. Their strongest association with alcohol dependence was with an intron 1 SNP rs1391175 (p = 0.05). We genotyped two of these six SNPs: for the intron 1 SNP rs2221020 Edenberg et al. found a trend association with alcohol dependence (p = 0.07) in contrast to our significant associations with AUD in both populations (p < 0.01). For the intron 8 SNP rs1497570, Edenberg et al. found no association (p = 0.65) in contrast to our significant results in both samples (p < 0.05). On the other hand, as in our study Covault et al (2008) have shown significant haplotype and SNP association with alcoholism in a haplotype block that extends from GABRG1 intron 2 to the intergenic region between GABRG1 and GABRA2 in two large groups of U.S. Caucasians (Covault et al, 2008). They genotyped 15 SNPs extending from GABRA2 intron 3 to GABRG1 intron 3 and found, as we did, that although the GABRA2 SNPs were located in
