Autoradiographic and electron microscopic studies of marrow in congenital dyserythropoietic anemia

Abstract

A 12 year old Caucasian girl with congenital anemia and episodic jaundice was studied. Hemolysis was not present as evidenced by a normal Cr51 red cell survival time. Congenital dyserythropoietic anemia type II (Heimpel) was diagnosed after finding a positive acidified serum test of the circulating red cells and marked erythroid hyperplasia with erythroblastic multinuclearity in a bone marrow aspirate. A bone marrow specimen was labeled with H3T in vitro and autoradiographs prepared. Electron microscopy was also done on the same specimen. The percent of uninucleated normoblasts labeling with H3T indicated normal DNA synthesis. However, only 2% of the binucleated and none of the multinucleated polychromatophilic normoblasts labeled with H3T, indicating decreased DNA synthesis in these forms. By electron microscopy, excessive membrane structures forming invaginations or cisternae and encompassing the circumference of the cell in varying degrees were seen in the majority of the normoblasts. The nuclear membrane appeared normal. Despite the abnormality, nuclear extrusion was noted in these cells. Small cisternae were also found at the periphery of the cell in about 1–2% of the mature erythrocytes. These findings are suggestive that the cells with more severe structural abnormalities and/or decreased DNA synthesis are destroyed intramedullary and the circulating red cells are derived from a less abnormal portion of precursors.