Congenital dyserythropoietic anemias.

The congenital dyserythropoietic anemias (CDAs) are a group of relatively rare inherited anemias that share in common ineffective erythropoiesis and morphologic abnormalities of mature red blood cells and their precursors. Three major types of CDA and a number of variants have been described. The diagnosis and categorization of these disorders are facilitated by microscopic examination of the blood and bone marrow and by serologic testing. Management of patients currently consists of observation and supportive care. Because patients with CDAs may be at significant risk for secondary hemochromatosis, they require monitoring for this condition. Splenectomy may be of benefit in certain cases in which the anemia is particularly severe. Over the past few years advances have been made in understanding the pathogenesis of these disorders, and it now appears that CDA II results from enzymatic defects in the cellular glycosylation pathway.