Abstract 23

Congenital erythopoietic anemia, type II, or CDA II, is the most common of all congenital erythropoietic anemias. It is characterized by: mild and intermittent jaundice, enlarged spleen and cholelithiasis, low reticulocyte count, seldom transfusion needs, small efficiency of splenectomy, late hemochromatosis rather frequent positivity of the Ham test. Parvovirus infection has exceptionally been reported, as well as extramedullar hematopoiesis. Its inheritance pattern is invariably recessive.

Reduction in the activities of some enzymes involved in glycan were also reported. However, the genes encoding N-acetylglucosaminyltransferrase II (chromosome 14), α-mannosidase II (chromosome 15) and its homologue, α-mannosidase II × (chromosome 5) have been dismissed. On the other hand, the candidate gene of CDA II was mapped to 20q11.2 in a set of Italian families and in a French kindred. Among Italian families there is a strong founder effect and a decreasing northward gradient appeared.

To confirm the founder effect and to allow the molecular studies on CDA-II an international registry was created. At October 1998 a total of 36 italian families and 16 foreign kindreds were enrolled with a patient overall number of 62.