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 a distinct haplotype block from GABRG1 SNPs, there was moderate LD between markers in the two blocks. Covault et al (2008) used only 4 SNPs to identify GABRG1 haplotypes in contrast to our 11 SNPs, nevertheless both our studies have identified GABRG1 haplotype associations with alcoholism. Our study expanded on this earlier result by demonstrating in two independent, ethnically diverse populations that the association between AUD and GABRG1 extended across a region that included all of GABRG1 and the downstream intergenic region.
