Hereditary spherocytosis associated with protein band 3 defect in a Swiss kindred.

A kindred with hereditary spherocytosis, in which 10 individuals were affected, was investigated. Gel electrophoresis of membrane proteins revealed a protein band 3 defect (densitometric reduction 14·4±7·0%). The erythrocyte morphology of unsplenectomized patients showed so-called pincered erythrocytes (about 1%), which were not present in the five splenectomized patients. Splenectomy also reduced anisocytosis and all parameters of haemolysis, while haemoglobin increased. The osmotic resistance was reduced in patients with protein band 3 deficiency. Erythrocyte filterability through 3 μm pores was decreased. A significant correlation was found between osmotic resistance and filterability. The membrane elastic modulus of erythrocytes was not affected. These results on structural and functional properties of protein band 3 deficient erythrocytes may contribute to a better understanding of this newly discovered form of hereditary spherocytosis.