Among the two major ethnic groups, Burmans showed greater diversity of G6PD deficiency mutations compared to Karen; among the 16 deficient subjects of Burman origin 10 had the Mahidol variant while among the 50 G6PD deficient subjects of Karen ancestry, 49 had Mahidol variant (P<0.01). This evidence concerns the gene G6PD and G6PD deficiency.