Decreased glycosylation of band 3 and band 4.5 glycoproteins of erythrocyte membrane in congenital dyserythropoietic anaemia type II.

We report a study of HEMPAS erythrocyte membrane glycoproteins in relation to proteolytic digestion and surface labelling with galactose-oxidase/NaB[3H]4. The proteolytic digestion of band 3, the major intrinsic glycoprotein of the human erythrocyte membrane, reveals an abnormality in the outer glycosylated segment of this protein. 3H incorporation in band 3 and band 4.5 glycoproteins after treatment with galactose-oxidase/NaB[3H]4 is reduced in HEMPAS red cells suggesting a defective glycosylation of these proteins. These findings together with the persistence of i antigen and the normal presence of I antigen lead us to conclude that erythroblastic membrane features may persist in HEMPAS erythrocytes.