Phenotypic expression of ferroportin disease in a family with the N144H mutation

Ferroportin is a putative transmembrane channel involved in the exit of iron out of the enterocytes, the macrophages and the hepatocytes. Mutations in the human gene coding ferroportin have been linked to an unusual form of iron overload, now referred to as "hemochromatosis type IV" or "ferroportin disease" characterized by a prevalent iron overload of macrophages and liver Küpffer cells. We report four patients from a same family with ferroportin disease associated with the N144H mutation. We show that in this family the mutation which is fully penetrant, may act through an increased iron export from macrophages as suggested by the unexpected absence of iron overload in the spleen and bone marrow detected by magnetic resonance imaging, that it co-segregates with a phenotype close to the classical form of HFE-associated hemochromatosis and was associated, in the oldest patient, with the development of hepatocellular carcinoma in a non cirrhotic liver. Our findings illustrate the existence of a genotype-phenotype relationship in "ferroportin disease", suggest that MRI may be useful in determining this phenotype and show that hepatocellular carcinoma may occur in these patients even without cirrhosis. This observation justifies careful follow-up of this subgroup of patients.