G6PD and G6PD deficiency: Therefore, if the frequency of the allele among controls approximates the population genotype frequencies, more than 90% (26/28) of G6PD deficiency alleles in females occur as heterozygotes and only 7.4% (2/28) as homozygotes; this is similar to the genotype frequencies in females predicted by the Hardy-Weinberg model (i.e., 1.5% homozygotes for deficiency, 21.3% heterozygotes, 77.3% G6PD normal) based on a G6PD deficient allele frequency of 12.1% (Chi2 = 1.03, p = 0.69).