G6PD and G6PD deficiency: For example, the widespread distribution of mutations that cause a deficiency in an enzyme called glucose-6-phosphate dehydrogenase (G6PD) mirrors the distribution of malaria and the African (A−) form of G6PD deficiency, a type of G6PD deficiency that is common in people of African origin, is known to provide partial protection against severe P. falciparum malaria—P.