Marker information including genetic map position, location within GABRA2 and the minor allele frequencies of the eleven SNPs genotyped within our Australian twin sample are listed in Table 2. Call rates of ≥98% were achieved for all SNPs except rs567926 where 96.9% of the sample was successfully genotyped. No SNPs showed significant deviations from Hardy-Weinberg equilibrium (HWE) at a p < 0.01 level. Discordant genotypes between MZ twins were identified using PEDSTATS and made up 0.12% of the data. The physical locations of, and linkage disequilibrium (LD) between, the 11 SNPs typed across the GABRA2 gene are presented schematically in Figure 1. Substantial LD was observed between seven markers spanning from intron 3 to the 3'UTR, with lower levels of LD (r2 < 0.3) observed 5’ to this major haplotype block. This is consistent with LD data (on a smaller number of people) from the HapMap database for CEPH families of European origin.
