Congenital Hemolytic Anemia with High-Sodium, Low-Potassium Red Cells

A young boy, his father and his grandfather were found to have erythrocytes with markedly reduced potassium and elevated sodium concentrations. The cells were abnormally permeable to sodium and potassium, and the active transport of these cations was increased. The cells were "stomatocytic" rather than spherocytic and had increased osmotic fragility and normal ATPase activity. In contrast to normal findings, ultracentrifugation studies revealed that the father's old red cells were less dense than his young cells. Young cells had a sodium concentration of 22, and old cells one of 116 mEq per liter of cells. These gross abnormalities of cation concentrations did not severely jeopardize red-cell lifespan. This disease mimics hereditary spherocytosis in its mode of inheritance and red-cell osmotic fragility, but differs in absence of spherocytes in peripheral blood, and in red-cell cation content.