Iron-Refractory Iron Deficiency Anemia (IRIDA) is a hereditary disorder associated with mutations in TMPRSS6.


Gene: TMPRSS6 (matriptase-2), a transmembrane serine protease expressed in the liver

Location: 22q12.3


Mechanism: TMPRSS6 normally downregulates hepcidin production by cleaving hemojuvelin. Excessive hepcidin inhibits iron absorption from the intestine and iron release from macrophages.


Inheritance: autosomeal recessive


Clinical features:

(1) chronic anemia

(2) light-colored hair

(3) no response to oral iron replacement

(4) some improvement with long-term parenteral iron therapy


Laboratory features:

(1) microcytic anemia with low serum iron concentration

(2) elevated serum hepcidin concentration

(3) increased hepcidin concencentration in the urine


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