Among 104 G6PD alleles including 73 alleles from hemizygous males, 27 alleles from heterozygous females, and 4 alleles from homozygous/compound heterozygous females with G6PD deficiency, G6PD Viangchan (871G > A) was the most common mutation and was detected in 48 chromosomes (46.2%). The gene discussed is G6PD; the disease is G6PD deficiency.