Congenital iron metabolism disorders
What is it?
Iron Refractory Iron Deficiency Anemia (or IRIDA) is a rare anemia characterized by a genetic iron deficiency. The disease is caused by excessive production of the hepatic hormone hepcidin, which has an inhibitory function on the intestinal absorption of iron and its recycling from the destruction of red blood cells in the spleen. The consequences are a decrease in serum iron levels, which leads to iron deficiency anemia. Due to the high level of hepcidin, anemia since childhood is resistant to treatment with oral iron, and is only partially responsive to the administration of intravenous iron.
How is it transmitted?
The disease is caused by mutations in the TMPRSS6 gene, which codes for the protein matriptase-2, the main inhibitor of hepcidin. It is transmitted in an autosomal recessive manner so that a couple of healthy carriers have a one in four chance of transmitting the disease to each of their children. Sporadic cases of IRIDA in heterozygotes (only one mutated TMPRSS6 gene) have been recorded, but in these cases the contribution of acquired factors in causing iron deficiency anemia cannot be excluded.
How is it diagnosed?
IRIDA is suspected in the case of moderate iron deficiency anemia, characterized, however, by extremely low levels of iron, MCV and MCH. In contrast to what is seen in common acquired iron deficiency anemia, ferritin can also be normal or slightly elevated. Frequent causes of iron deficiency (diet with iron deficiency, impaired absorption and chronic blood loss) and inflammatory anemia (in turn, characterized by increased production of hepcidin) should be excluded. Diagnostic confidence is achieved through molecular testing and demonstration of TMPRSS6 mutations. It is likely that in the future, the dosage of serum hepcidin (currently not yet available for clinical use) will facilitate the diagnostic process.
How is it treated?
The disease is benign and treatable with intravenous iron, at least partially. It is important to control anemia with periodic blood and iron tests, especially during childhood, during growth and with excessive menstrual loss, and during pregnancy.
Where do we treat it?
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