Two female patients were heterozygous for a variant associated with G6PD deficiency (the Viangchan variant): 1 in the tafenoquine group, who had a G6PD enzyme level of 5.57 IU per gram of hemoglobin, and 1 in the primaquine group, who had a G6PD enzyme level of 5.41 IU per gram of hemoglobin; neither patient had clinically important declines in hemoglobin level (declines of 2.3 g per deciliter and 1.8 g per deciliter). This evidence concerns the gene G6PD and G6PD deficiency.