Congenital dyserythropoietic anemias

The congenital dyserythropoietic anemias (CDAs) are an uncommon and heterog eneous group of disorders characterized by markedly ineffective erythropoie sis and, usually, striking dysplastic changes in erythroblasts. Each of the three originally described forms, designated CDA types I to Iii, is define d by the presence of distinctive morphologic (including ultrastructural) ab normalities in erythroblasts. CDA type II is also characterized by a marked reduction in polylactosamine structures associated with the erythryocyte m embrane glycoprotein, band 3 (detected by sodium dodecyl sulfate polyacryla mide gel electrophoresis), and, usually, a positive result on the acidified serum lysis test. The course of CDA is often complicated by cholelithiasis . Even patients who have not had transfusions sometimes develop substantial iron overload. Recent studies have extended our knowledge on the clinical manifestations of CDA types I and III and have revealed the existence of fo rms of CDA distinct from types I to III, Information is now available on th e chromosomal localization of the genes involved in CDA types I and II and in the Swedish cases of CDA type III. A few patients with CDA type I have b een treated with interferon-cr,, with a good response. (C) 2000 Lippincott Williams & Wilkins, Inc.