G6PD deficiency is the most common human genetic condition, with potential lifelong clinical implications.1,2,23 Glucose-6-phosphate dehydrogenase deficiency is highly prevalent in malaria-endemic populations, where resources are limited.24 Primaquine and tafenoquine, both 8-aminoquinolines, when given with blood-stage antimalarials can cure patients of P. vivax but may also cause clinically relevant hemolysis in patients with decreased G6PD activity. The gene discussed is G6PD; the disease is malaria.