Rh deficiency syndrome

A rare constitutional hemolytic anemia due to a red cell membrane anomaly characterized by lack or severe reduction of Rh blood group antigens, resulting in increased osmotic fragility of red blood cells and chronic hemolytic anemia of varying severity with stomatocytosis and spherocytosis. Two types of the syndrome arising from independent genetic mechanisms have been distinguished: the regulator type is caused by defects of the Rh associated glycoprotein (encoded by the <i>RHAG</i> gene), while the amorph type is due to mutations at the <i>RH</i> locus itself.