Secondary analysis using a broader definition of alcoholism that includes additional individuals (COGA definition; Table 1) shows more SNPs significantly associated, particularly in the 5′ portion of GABRR2. The associated SNPs within each portion of GABRR1 and GABRR2 are in LD with each other (Figure 3). Both regions of association cover the 5′ promoter to the intron 1 region of each gene, suggesting that they may affect the regulation of these genes. Several SNPs in the two associated regions (SNPs 25-27 and 36, and SNPs 60-62) are located in highly conserved regions, suggesting potential functional roles in gene expression. The two intronic SNPs in UBE2J1 (SNPs 67 and 68) are in LD with the upstream region of GABRR2 (Figure 3, and may also affect expression of GABRR2.
