Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ INTRODUCTION ++ Congenital dyserythropoietic anemias (CDA) are a heterogeneous group of disorders characterized by anemia, the presence of multinuclear erythroid precursors in the marrow, ineffective erythropoiesis, and iron overload. Although rare, uncovering the molecular basis of CDA has helped unravel novel aspects of the cell biology of erythropoiesis. Three types of CDA have been distinguished. In addition, a number of patients with forms of congenital dyserythropoietic anemia that do not fit these categories have been described. ++ CDA TYPE I ++ Clinical and Laboratory Features ++ Presents in infancy or adolescence. Autosomal recessive inheritance, caused by mutations of the CDAN1 gene (codanin-1), encoding a cell-cycle-regulated protein of yet unknown function; homozygosity is often associated with consanguinity. In a number of patients, only one CDAN1 allele is identified with a mutation; other causative genes suspected because in rare CDA I families, no mutations of the CDAN1 gene found. Moderately severe macrocytic anemia (approximately 9.0 g/dL). Hepatomegaly and cholelithiasis are common. Splenomegaly increases with age. Specific morphologic findings of CDA type I are summarized in Table 7–1 and exemplified in Fig. 7–1. Dysmorphologic features may be present, the most common involve the bones of the hand and the foot. Other, less common features are small stature, almond-shaped blue eyes, hypertelorism (increased distance between two body parts or organs), and micrognathism. ++Table Graphic Jump LocationTABLE 7–1MAIN FEATURES OF TYPES I, II, AND III CONGENITAL DYSERYTHROPOIETIC ANEMIASView Table|Favorite Table|Download (.pdf) TABLE 7–1 MAIN FEATURES OF TYPES I, II, AND III CONGENITAL DYSERYTHROPOIETIC ANEMIAS CDA Type Light Microscopy Electron Microscopy Serology Inheritance I Most erythroid cells abnormal: double nuclei, internuclear chromatin bridges (Fig. 7–1) Widened nuclear pores, spongy appearance of the heterochromatin, invasion by the cytoplasm containing various organelles No serologic abnormalities Autosomal recessive II Mature stage erythroblasts with two or more nuclei, lobulated nuclei, karyorrhexis, pseudo-Gaucher cells (Fig. 7–1) Endoplasmic reticulum cisternae lining the inner surface of the red cell plasma membrane Cells containing the HEMPAS antigen are lysed by 30% of acidified normal sera; strong reactivity with anti-"i" autoantibodies Autosomal recessive III Giant erythroblasts, up to 50 μm in diameter, with up to 12 nuclei, basophilic stippling Clefts and blebs within nuclear areas, some iron-filled mitochondria, autophagic vacuoles and myelin figures in the cytoplasm No clearly defined abnormalities Autosomal dominant (not all cases) Source: Williams Hematology, 8th ed, Chap. 39, Table 39–1, p. 514. ++ FIGURE 7–1 Light microscopy of marrow. A. Congenital dyserythropietic anemia type I. Note the intranuclear chromatin bridge marked by an arrow. This bridge is unusually long. B. Congenital dyserythropietic anemia type II. The two arrows point to binucleate erythroblasts, characteristic of this type. (Used with permission from Dr. Odile Fenneteau.) (Source: Williams Hematology, 8th ed, Chap. 39, Fig. 39–2, p. 515.) Graphic Jump LocationView Full Size|Favorite Figure|Download Slide (.ppt) ++ Differential ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. What is MyAccess? Create a FREE MyAccess profile to: Use this site remotely Bookmark your favorite content Track your self-assessment progress and more!