CDA-1 CDA anemia type 1 presents as moderate to severe
macrocytic anemia with symptoms like fatigue, weakness, and pale skin, often presenting in childhood. It is also associated with enlarged spleen and liver. The bone marrow shows abnormal
chromatin under the microscope. It is caused by a mutation in the
CDAN1 or CDIN1 gene, and has
autosomal recessive inheritance.
CDA-2 Features of congenital dyserythropoietic anemia type 2 (CDA II) include enlarged spleen (
splenomegaly),
jaundice,
gallstones, and often
iron overload. Under the microscope, the bone marrow shows a high number of
erythroblasts with two
nuclei. The cause is a mutation in the
SEC23B gene, and has autosomal recessive inheritance. It is the most common form of CDA, and is also known as HEMPAS (hereditary erythroblastic multinuclearity with a positive acidified serum test).
CDA-3 This is extremely rare; it has only been found in three families. It is characterized by mild to moderate anemia and the presence of giant erythroblasts in the bone marrow, with multiple nuclei. It can be caused by a mutation in the
KIF23 gene (in which case inheritance is autosomal dominant) or the
RACGAP1 gene (in which case inheritance is autosomal recessive). The proteins from these genes are essential for the
cytokinesis phase of
cell division.
CDA-4 This is a moderate to severe anemia which is evident at birth and can potentially be detected during pregnancy. In severe cases, the unborn child may have
hydrops fetalis (swelling caused by fluid accumulation before birth). It is extremely rare; only 10 cases have been diagnosed worldwide. In each case, the cause is a mutation of the
KLF1 gene, which is necessary for the proper maturation of red blood cells. Unlike types 1-3, this is a
de novo mutation which was not inherited.
Other types These include
Majeed syndrome and some instances of
sideroblastic anemia. ==Signs and symptoms==