Testing families with HFE-related hereditary haemochromatosis.

HFE-related hereditary haemochromatosis is the most common autosomal recessive disorder in the Caucasian population. In 1996 the responsible gene (called HFE) was identified. Two mutations (C282Y and H63D) are considered most important and occur frequently in the Caucasian population. We describe a family of an affected proband in which first- and second-degree relatives were tested phenotypically and genotypically. In second-degree relatives both C282Y homozygosity as well as compound heterozygosity were found. Family testing can be useful to detect persons who will possibly develop iron overload. We must be aware that testing first-degree relatives only carries a 2.5% chance that persons at risk of developing iron loading will not be detected. Cascade screening of second-degree relatives might be cost-effective.