Iron and haemochromatosis.

There have recently been considerable advances in the understanding of the inheritance of idiopathic haemochromatosis (McKusick 23520). The disorder is determined by a locus closely linked to the HLA loci on the short arm of chromosome 6. There is a recessive mode of transmission. The gene frequency may be as high as 0.05 in some parts of the world. HLA typing makes it possible to identify family members who are homozygous for idiopathic haemochromatosis and measurement of transferrin saturation and serum ferritin concentration will identify those with iron overload. Treatment is by regular phlebotomy. Few advances have been made in the 50 years in the understanding of the abnormality which permits the increased absorption of iron and which causes the iron overload.