There was one haplotype block extending from rs12511372 in intron 1 of GABRG1 to rs1504501 distal to the gene, a distance of 155 kb (Figure 2). Twelve of the 16 SNPs within the haplotype block showed significant associations with AUD (Table 1). There were 7 haplotypes with ≥ 0.01 frequency that accounted for 0.93 of the haplotype diversity. From Figure 2 it can be seen that there are two cladistic groupings of haplotypes: H1 – H4 and H5 – H7. Haplotypes H1 – H4 were more common in alcoholics than non-alcoholics (0.54 vs 0.41). The other 3 haplotypes (H5 – H7) were more abundant in non-alcoholics compared with alcoholics (0.59 v 0.46): (H1 – H4) vs (H5 – H7): χ2 = 8.8, 1 df, p = 0.003; global analysis: χ2 = 21.4, 6 df, p = 0.002.
