Electron and Light Microscopic Study of the Erythroblasts of Patients With Congenital Dyserythropoietic Anemia

The morphological changes of erythroblasts in congenital dyserythropoietic anemia type I have been analyzed by light and electron microscopy. The results support our earlier assumption, that this hereditary disorder of erythropoiesis is a disease entity and is not identical with any of the previously described hereditary hematological diseases. Characteristic morphological aberrations consist of widening of nuclear membrane pores, condensation, vacuolization and disintegration of the nuclear chromatin, structural changes of the nucleolus, appearance of myelin figures, and final autolysis of the cells. All changes are restricted to erythroblastic cells beyond the stage of the proerythroblast. The biochemical basis of this abnormality is not known. It leads to severe ineffective erythropoiesis with anemia, increased total hemoglobin turnover, and secondary hemochromatosis.