Chronic severe hemolytic anemia due to G-6-PD Charleston: A new deficient variant

Abstract

An 11-year-o'.d Negro boy with a history of neonatal jaundice requiring exchange transfusion had a severe hemolytic episode at 8 years of age. A diagnosis of nonspherocytic congenital hemolytic anemia due to G-6-PD deficiency was made at that time. The red cells of the patient contained a level of G-6-PD activity approximating 14 per cent of normal. The residual enzyme was partially purified and characterized. It proved to be electrophoretically rapid. The Michaelis constant (K m ) for G-6-P was diminished and that for NADP increased. The enzyme had greatly increased utilization of deamino-NADP and slightly increased utilization of 2-deoxyglucose-6-phosphate. The pH optimum curve was slightly bimodal. Like most other G-6-PD variants associated with congenital nonspherocytic hemolytic anemia, the enzyme was thermally labile. This enzyme represents a new deficent variant, G-6-PD Charleston. The patient continues to have chronic severe hemolysis. Two brothers presumably died of the same enzyme deficiency. The erythrocytes of two living brothers contain G-6-PD A-, The mother is heterozygous for the two variants.