The abnormal surface characteristics of the red blood cell membrane in congenital dyserythropoietic anaemia type II (HEMPAS).

The red blood cell membranes of patients with congenital dyserythropoietic anaemia Type II (CDA-II) were found to be abnormal. They had altered antigenic characteristics, decreased electrophoretic mobility, decreased sialic acid content, and abnormal filtration through polycarbonate filters. Proteins extracted from the CDA-II erythrocytes showed a different banding pattern on polyacrylamide gels compared to normal erythrocytes. Erythrocytes from clinically unaffected siblings and parents showed similar but less striking abnormalities of antigenic surface characteristics and banding patterns on polyacrylamide gels with nearly normal surface charge, sialic acid content, and filtration properties. These studies suggest a correlation between the degree of membrane abnormality and the clinical state of the CDA-II family member, demonstrate the erythrocyte in the heterozygote state is not normal, and support the concept of CDA-II as an autosomal recessive disease.