A glucose 6-phosphate dehydrogenase Gd (-) Castilla variant characterized by mild deficiency associated with drug-induced hemolytic anemia.

Erythrocyte G-6-PD deficiency is an X-chromosome-linked hereditary trait which is common in many ethnic groups. A deficiency of G-6-PD in red cells is often associated with hemolytic anemia. This report defines a new variant designated as Gd (-) Castilla, which is associated with drug-induced hemolysis. The red cell G-6-PD activity of the variant subject is about 20% of normal. The variant enzyme is thermolabile in vitro and it has faster than normal anodal electrophoretic mobility and normal substrate affinity. The hemolytic problem of the subject might be correlated to sensitivity to NADPH inhibition and molecular instability of the variant enzyme.