The congenital dyserythropoietic anaemias

Congenital dyserythropoietic anaemias (CDA) are a category of rare genetic diseases that affect erythropoiesis. Dyserythropoiesis is associated with a bnormal erythroblasts and leads to altered red cells, the amount of which i s insufficient. There are three main, well-defined CDAs, CDA I, II and III. Their characterization is based on a careful examination of the bone marro w under light and electron microscopes. In addition, a number of rare or un ique forms of dyserythropoiesis have been reported. At least with respect t o CDA I to ill, the clinical evaluation is reaching an ever increasing refi nement: age of discovery, determinants of iron overload and/or biliary comp lications. Over the past few years, a more promising breakthrough has been the localization of the genes responsible for CDA I, II and III, that is, 1 5q15.1-q15.3, 20q11.2 and 15q21-q25, respectively. Epidemiological studies have now become possible. The identification of the genes is pending.