A defect in the protein kinase-mediated phosphorylation of erythrocyte membrane proteins, previously unrecognized in stomatocytosis, was discovered in a boy with hereditary stomatocytosis and severe hemolytic anemia. The high-sodium, low-potassium erythrocytes of this patient were remarkably permeable to both sodium and potassium. The rate of ouabain-inhibitable active cation transport was more than ten times normal and was sustained by an increase of similar magnitude in glycolysis. The deformability in vitro of fresh stomatocytes was reduced and deteriorated further after a brief period of incubation with glucose. Ferrokinetic studies showed that these rigid cells were sequestered by the spleen. When stomatocytes were deprived of glucose in vitro, ATP depletion and ATPase cation pump failure rapidly ensued. Because of their permeability defect, such depleted cells rapidly became swollen and lysed. Prolonged entrapment in acidic, hypoglycemic regions of the spleen would recapitulate these unfavorable events in vivo. In this regard, splenectomy was followed by an improvement in erythrocyte survival, although evidence of continuing hemolysis was obtained.

Congenital nonspherocytic hemolytic anemia in an adult male of Scandinavian ancestry was associated with virtual absence of G6PD activity in red cells. Characterization of G6PD purified from leukocytes using standard WHO techniques revealed diminished electrophoretic mobility, marked lability on heating at 46 degrees C, normal pH optimum and utilization of alternate substrates (2-deoxy G6P, D-amino NADP), elevated Km NADP, and striking susceptibility to NADPH inhibition. The variant G6PD, which appears to be unique, has been designated G6PD San Francisco. An unusual feature of the variant enzyme, susceptibility to inactivation by brief periods of dialysis, could be prevented by addition of 200 microM NADP to the dialysis solution. In red cells, where G6PD activity was essentially absent, regeneration of reduced glutathione was totally curtailed in vitro, while in leukocytes, where residual G6PD activity was approximately 60% of normal, hexose monophosphate shunt activity, oxygen consumption during phagocytosis, and bacterial killing were unimpaired. Thus, instability of the variant enzyme rather than its unfavorable kinetics appeared to be an important determinant of abnormal cell function.

Congenital nonspherocytic hemolytic anemia in an adult male of Scandinavian ancestry was associated with virtual absence of G6PD activity in red cells. Characterization of G6PD purified from leukocytes using standard WHO techniques revealed diminished electrophoretic mobility, marked lability on heating at 46 degrees C, normal pH optimum and utilization of alternate substrates (2-deoxy G6P, D-amino NADP), elevated Km NADP, and striking susceptibility to NADPH inhibition. The variant G6PD, which appears to be unique, has been designated G6PD San Francisco. An unusual feature of the variant enzyme, susceptibility to inactivation by brief periods of dialysis, could be prevented by addition of 200 microM NADP to the dialysis solution. In red cells, where G6PD activity was essentially absent, regeneration of reduced glutathione was totally curtailed in vitro, while in leukocytes, where residual G6PD activity was approximately 60% of normal, hexose monophosphate shunt activity, oxygen consumption during phagocytosis, and bacterial killing were unimpaired. Thus, instability of the variant enzyme rather than its unfavorable kinetics appeared to be an important determinant of abnormal cell function.