[Hemolysis and hemolysis mechanisms in congenital dyserythropoietic anemia (CDA) of type I. II., III].

On the basis of clinical symptoms, bone marrow morphology, electronmicroscopy and serological tests congenital dyserythropoietic anemia (CDA) was diagnosed in 3 families and identified as CDA type I, II, III respectively. Aside from intramedullary hemolysis, members of all three families showed peripheral hemolysis, in some cases severe, which was mediated through splenic (in all types) and additional intravascular destruction in types I and II. The underlying cause of the peripheral hemolysis appears to be reduced deformability of erythrocytes, as documented by reduced filterability. The latter appears to be caused, at least in type II, by an increase in viscosity of the cytoplasm which in turn is probably related to increased susceptibility to oxidative injury leading to inclusion body formation. Splenectomy in one patient with CDA II led to a definite reduction of hemolysis and cessation of hemolytic crises.