Congenital dyserythropoietic anemia type II: serologic and morphologic family study.

A 29-year old woman with a history of chronic anemia, jaundice, and splenectomy was found to have congenital dyserythropoietic anemia type II (CDA II), based on the following: marrow erythroid hyperplasia, abundance of binucleated erythroblasts, electron microscopic evidence of double membranes lining the cell membrane, erythrocyte lysis in the acidified serum test, erythrocyte agglutination and lysis by anti-i antibodies. Three healthy relatives (mother, father, and brother) of the patient had marrow erythroid hyperplasia and a percentage of binucleated erythroblasts that was higher than normal. A structural alteration of the nuclear membrane was detected in some of their erythroblasts. Furthermore, the erythrocytes of the father and the brother were agglutinated by anti-i antibodies. This observation is consistent with a recessive mechanism of inheritance, and suggests that heterozygosity for CDA II can be somatically expressed at different levels.