PRIMARY HAEMOCHROMATOSIS

See article in Norwegian on haemachromatosis from Norsk tidsskrift for Den norske legeforening: Hemokromatose

Primary haemochromatosis is a recessive*) genetic condition where the iron absorption is increased in relation to the requirements of the body. With a daily uptake from the diet of 1-3 mg of iron in excess of needs, 20-40 g of iron will have accumulated in the body during 40-50 years. This iron overload takes place especially in the liver, but later also in other organs and will lead to pathological changes of the tissues.

*)The mutated gene must exist in double dose, ie., homozygous (hh).

With one mutated and one normal gene (heterozygous, Hh; H = normal gene (wild type)) the iron absorption is somewhat increased. A normal diet without extra iron doses will therefore not lead to pathological overload.

Mutations in the socalled HFE-gene, of which C282Y is the most important mutation (described in 1996), accounts for 90% of primary haemochromatosis. Later several other mutants have been found (not in the HFE-gene), which also cause iron overload.

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Prevalence of primary haemochromatosis

• Primary haemochromatosis is considerably more common than thought in the past. Previous assumption: 1 per 10 000 individuals was homozygous for this condition.

• At present we know that the prevalence of primary haemochromatosis is: 0,2 – 0,7% homozygous (hh) and 8 – 15% heterozygous (Hh) individuals.

Prevalence in Norway:

• hh: 3,4‰ among first-time blood donors (Bell et al. J Hepatol 1997;26:272-9)
• hh: ca. 5‰ Health screening in mid-Norway 1995-97 (HUNT; Åsberg A
  et al. Scand J Gastroenterol 2001;36:1108-15)

which gives the following estimates:

• 20 000 homozygotes and 600 000 (15%) heterozygotes

Important clinical tests

• Transferrin saturation (= serum iron/TIBC x 100%; ’iron saturation’; increased already in young age)
• Serum ferritin (iron stores; increase with age)

INDICATIONS OF PRIMARY HAEMOCHROMATOSIS

• transferrin saturation > 50 % for women and 55 % for men * (fasting; measure with 1-2 weeks interval)
• serum ferritin > upper cut-off values

OTHER TESTS

• Liver biopsy
• Gene test (C282Y mutation)

*) Reference values for transferrin saturation: 15-45%

Transferrin saturation - see Appendix.