Congenital dyserythropoietic anemia type IV (CDAN4) is an autosomal dominant red blood cell disorder characterized by ineffective erythropoiesis and hemolysis resulting in anemia. Circulating erythroblasts and erythroblasts in the bone marrow show various morphologic abnormalities. Affected individuals with CDAN4 also have increased levels of fetal hemoglobin (summary by Arnaud et al., 2010). For a discussion of genetic heterogeneity of congenital dyserythropoietic anemia, see CDAN1 (224120).

Sideroblastic anemia-5 (SIDBA5) is an autosomal recessive hematologic disorder characterized by abnormal iron accumulation in the mitochondria or erythroid cells. The pathologic iron deposits appear to ring the nucleus, resulting in a 'ringed sideroblast' on pathologic examination. Affected individuals have congenital hypochromic microcytic anemia apparent in childhood; they may also develop thrombocytopenia or pancytopenia (summary by Crispin et al., 2020). For a discussion of genetic heterogeneity of sideroblastic anemia, see SIDBA1 (300751).