Ultrastructural studies of an unusual variant of congenital dyserythropoietic anaemia type II.

Electron microscopy of a new variant of congenital dyserythropoietic anaemia type II has yielded several unexpected results. The remarkable features include the relatively high percentage of erythrocytes with peripheral cisternae, the involvement of all bone marrow precursor cells, and the presence of ultrastructural defects in the granulocytes and platelets and on the cell surface of the erythrocytes. Experiments with vinblastine showed that this drug was capable of producing (in vitro) strikingly similar ultrastructural defects in healthy erythrocytes.