[Hereditary hemochromatosis].

Four types of hereditary haemochromatosis have been identified. Type 1 is due to a point mutation in the HFE gene (C282Y) and leads via an increase in intestinal iron absorption to iron overload and organ damage. Type 2 is a juvenile form with manifestation before age 30; it affects both gender and is associated with severe cardiomyopathy and hypogonadism. The genetic defect of type 3 is located on chromosome 7q22 and affects the transferrin receptor 2. The consequences of type 3 are similar to those of type 1. The autosomal-dominant type 4 is located on chromosome 2q32 and affects the basolateral iron carrier ferroportin 1. In contrast to types 1 and 3 iron deposits in type 4 are seen predominantly in macrophages; in type 4 serum ferritin is significantly increased although transferrin saturation is only slightly abnormal. The prognosis of haemochromatosis is normal when phlebotomy therapy is started prior to manifestation of cirrhosis or diabetes. Screening strategies should be implemented to improve early detection.