Allelic and genotypic comparisons between genders showed significant differences only in patients. In this group, the frequency of the A1 allele (Table 2) was higher in males than in females (24.4% vs. 14.9%; χ2 = 5.79, df = 1, P = 0.016). However, differences between male and female patients regarding genotype distribution (Table 3) did not reach statistical significance (χ2 = 5.37, df = 2, P = 0.068). DRD2 allele and genotype frequencies, however, were not significantly different between male and female controls.
