When examined globally, none of the well-studied candidate genes demonstrate impressive variant differences between cases and controls. More specifically, only one SNP reported in SAGE (rs925946 upstream of BDNF, p=0.0006) in the 54 candidate genes had a p value less than 0.0009, a corrected p value for the number of genes (.05/54= 0.0009). Additionally, the overall number of variants with p<.05 and p<.01 is close to that predicted by chance considering the total number of SNPs examined in all proposed candidate genes. Although the individual p values for variants in the examined candidate genes are modest, a few candidate genes have a large portion of SNPs with p<.05 (Table 3). The results support further research into whether GABRA2, which was the candidate gene with the largest proportion of SNPs with p< .05 (55%), contributes to risk of developing alcohol dependence. BDNF and HTR1A also had more than one fifth of SNPs with p<.05, indicating that these genes merit further investigation to elucidate their potential contribution to alcohol dependence.
