Variant type of congenital stomatocytosis

A 52-year-old female with congenital stomatocytosis showed hemolytic anemia, an increased mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC), reticulocytosis and an increased osmotic fragility. Lipid and protein content of membranes, the activities of membrane-associated enzymes in erythrocytes and the elution pattern of hemoglobin were normal. Erythrocyte Na+ influx was moderately increased and Na+ efflux, particularly ouabain-insensitive Na+ "leak-out" was also increased. K+ concentration of erythrocytes was abnormally low with a slightly increased Na+ content. These phenotypes are very rare, and should be classified as a variant type.