X-linked sideroblastic anemia is a hereditary enzyme disorder in which the body has adequate iron but is unable to incorporate it into hemoglobin.
X-linked sideroblastic anemia is the hereditary form of sideroblastic anemia, also known as iron overload anemia or sideroblastosis. Another, more common type of sideroblastic anemia is called acquired sideroblastic anemia.
In sideroblastic anemia, iron enters a developing red blood cell and is not incorporated properly into the hemoglobin molecule (the cell's oxygen carrier). This causes iron to accumulate in the mitochondria and sideroblasts. The defective hemoglobin then transports oxygen poorly, resulting in decreased tissue oxygenation.
This build-up of iron gives the cell nucleus its ringed appearance, called ringed sideroblast, which is the primary sign of sideroblastic anemia.
Sideroblastic anemia is often mistaken for iron deficiency anemia, but tests usually reveal normal or increased levels of iron.
X-linked sideroblastic anemia
The hereditary form of the disorder is rare. The primary type of inherited sideroblastic anemia was first described in 1945 by Thomas Cooley. He identified cases of X-linked sideroblastic anemia in two brothers from a family with a six-generational history of the inherited disease. The genetic abnormality that causes X-linked sideroblastic anemia was identified almost 40 years later. Identification has aided diagnosis of this disorder.
X-linked sideroblastic anemia nearly always manifests in infancy or childhood.
Other inherited forms of sideroblastic anemia
There are other inherited forms of sideroblastic anemia, which are also rare. A rare autosomal recessive form of inherited sideroblastic anemia occurs in both males and females of affected families. Autosomal dominant inheritance has also been reported. The abnormalities that cause these anemias are not yet identified. Also, Pearson's syndrome, an inherited disorder caused by abnormal mitochondria, is sometimes called sideroblastic anemia with marrow cell vacuolization and exocrine pancreatic dysfunction.
Jennifer F. Wilson MS, Thomson Gale, Gale, Detroit,