When applying the dTDT to the alcohol dependence data from COGA, nearly twice the number of SNPs (166 vs. 93) were found having p-values <10− 4 . Further, to maximally make use of the available sample data, we combine case-control study and dTDT with the MH test. This potentially increases our sample size and makes the method more robust to uncontrolled factors. As a result, we have one signal in gene STK40 with p-value that attains a genome-wide significance level. A large number of SNPs are found having p-values <10− 4. Several clusters of SNPs by distance with p-values <10− 5 are found in various genes across the genome.
