G6PD and G6PD deficiency: Glucose-6-phosphate dehydrogenase deficiency is an inherited X-linked enzymopathy present in up to 20% of malaria-endemic populations.9 Males have a single copy of the gene and are either hemizygous G6PD deficient with < 30% of normal G6PD activity or normal.10 By contrast, females have two copies of the gene and can be homozygous G6PD normal or deficient, or heterozygous.