This study was reasonably powered to replicate previous findings. Under the dominant mode of inheritance, a G allele frequency of ∼13% consistent with our data, and conservatively assuming population prevalence of 0.5%, we estimate that the current study had 80% power to detect a genetic relative risk of ∼1.45 and higher in the ethnic Bulgarian male sample alone at the α = 0.001 significance level; and 80% power for a genetic relative risk of ∼1.32 at α = 0.05. These are lower than the smallest estimated relative risk of ∼1.6 from previous positive association results. The results are virtually identical assuming co-dominance. Power is low to detect a recessive mode of inheritance with 17.3% frequency of 118G allele.
