Hemochromatosis in the era of genetics.

A simple test is now available for detecting a mutation present in the homozygous state in 90% of hemochromatosis patients. This test obviates the need for performing a liver biopsy for diagnostic purposes. Liver biopsy can provide prognostic information, however, in patients with massive hepatic iron overload. Detection of the mutation allows to rule out three differential diagnoses, of which two are common diseases. In familial studies, the genetic test has superseded HLA phenotype determination.