Congenital Hemolytic Anemia with High Sodium, Low Potassium Red Cells

Evaluation of the erythrocytes of a child with hemolytic anemia of unknown cause showed that the intracellular concentrations of sodium and potassium were 100 mEq per liter of cells and 40 mEq per liter of cells respectively. Such values have never previously been recorded in human erythrocytes. Further studies showed that the cation abnormality was due to a vast increase in permeability to monovalent cations, with a concomitant massive increase in active cation pumping. Permeability to divalent cations and anions and to nonelectrolytes was normal. Thus, a defect in mean pore size or charge was not detected. Comparisons of these cells to erythrocytes in hereditary spherocytosis led to the conclusion that increased cation transport rates do not invariably result either in membrane phospholipid loss or in microspherocytic changes.