Inherited disorders of iron metabolism

To discuss inherited iron disorders, their pathophysiology and clinical implications in the light of the recent advances in our knowledge of iron metabolism and its regulation.

In previous years the molecular mechanisms of cellular iron uptake and release and the cellular and systemic iron homeostasis have been substantially clarified. New proteins (hepcidin, hemojuvelin, HFE, TFR2 and ferroportin), mutated in hereditary hemochromatosis, have been identified with a crucial role in iron regulation. These advances have modified our understanding of the pathophysiology of hemochromatosis, now considered a disorder either due to hepcidin deficiency or (rarely) due to hepcidin resistance. Novel genetic forms of iron-related microcytic anemia have been identified, due to defects of iron transport/utilization or to TMPRSS6 deficiency and hepcidin hyperproduction, as occurs in iron-refractory iron deficiency anemia (IRIDA). A role for hepcidin has been identified also in acquired conditions, as in iron-loading anemias and in anemia of chronic diseases and inflammation.

Advances in basic research have improved the classification and diagnosis of genetic anemias and iron overload and are paving the way towards the development of drugs that target the molecular lesions.