PURPOSE: Recent discoveries in molecular mechanisms of iron metabolism have changed the classical view of hereditary iron overload conditions. We present natural mutations in newly discovered genes and related phenotypes observed in patients with different form of haemochromatosis. CURRENT KNOWLEDGE AND KEY POINTS: Most haemochromatosis patients are homozygous for the C282Y mutation in the HFE gene. Ferroportin, TFR2, hemojuvelin and hepcidin mutations also cause iron overload. Recent data support the hypothesis that haemochromatosis should no longer be considered a monogenic disease but rather an oligogenic disorder. Several results suggest that haemochromatosis could result from digenic inheritance of mutations in HFE and HAMP. FUTURE PROSPECTS AND PROJECTS: Other modifier genes probably influence penetrance in C282Y homozygous patients. Such genes could enhance or reduce the phenotypic expression in various iron overload conditions.
Service de génétique moléculaire médicale et UPRES EA 2629, CHU d'Amiens, université de Picardie-Jules-Verne, 3, rue des Louvels, 80036 Amiens cedex, France. estelle.cadet@u.picardie.fr
