Update on hereditary hemochromatosis and the HFE gene.

Hereditary hemochromatosis (HHC) is the most common inherited single gene disorder in people of northern European descent. Hereditary hemochromatosis is characterized by increased intestinal absorption of iron leading to its deposition into multiple organs. The classic description of HHC is bronze diabetes in a patient with cirrhosis. Hereditary hemochromatosis is increasingly being diagnosed at an earlier, less symptomatic stage. Diagnosis is based on an elevated fasting early morning transferrin saturation. Treatment is by phlebotomy, which, if initiated before the development of cirrhosis or diabetes, is associated with a normal life expectancy. Recently, a gene associated with HHC was discovered and named HFE. Two point mutations of this gene have been referred to as C282Y and H63D. Several US and European studies have found that 60% to 93% of patients with suspected HHC are homozygous for C282Y. Positive results of HFE gene testing may eliminate the need for a liver biopsy in selected cases. The greatest utility of HFE gene testing will likely be in screening family members of an identified proband and in helping to resolve ambiguous cases.