G6PD Deficiency and Chronic Hemolysis: Four New Mutants—Relationships Between Clinical Syndrome and Enzyme Kinetics

G6PD deficiency of the common type (Gd^A- and Gd^{Mediterranean}) results in extremely mild chronic hemolysis. In contrast, 65 males (from 47 unrelated families) have been reported with a different syndrome of severe chronic hemolysis associated with a superficially similar deficiency in the activity of G6PD. Five new such patients (from four unrelated families) are reported. Biochemical characterization of the erythrocyte G6PD from these patients indicates that these four mutant enzymes are different from each other and from previously reported variants. These new mutants have tentatively been named G6PD New York, G6PD Englewood, G6PD Rotterdam and G6PD Den Haag. The congenital nonspherocytic hemolytic anemias associated with G6PD deficiency appear to be an extremely heterogeneous group from the point of view of biochemical kinetics. The relationships between the clinical syndrome and the various biochemical enzyme characteristics are discussed in the light of the information presently available.