Congential dyserythropoietic anemia--type IV.

Congenital dyserythropoietic anemia is characterized by ineffective erythropoiesis and increased numbers of multinucleated red cell precursors in the marrow. This syndrome has been subclassified on the basis of morphologic differences in the red cell precursors. Type I is characterized by megaloblastoid erythropoiesis and macrocytosis; Type II, by normoblastic multinuclearity and normocytosis; and Type III, by frequent giant multinucleated erythroblasts and macrocytes. Type II is further distinguished from the other types by serologic and ultrastructural abnormalities. The patient presented in this report does not fit any of the above categories; her red cells are similar to Type II congenital dyserythropoietic anemia cells, but no characteristic ultrastructural or serologic abnormalities are present. It is suggested that this patient may represent an additional variant of congenital dyserythropoietic anemia, Type IV.