What are the symptoms? The effects of excess iron in the body depend more on the rate and age at which it occurs than on the cause. In young children and adults, there are effects on the heart and hormone system: there are palpitations and irregularities of the heartbeat, which can be dangerously rapid; the pumping function can also fail, causing breathlessness and swelling of the legs and abdomen. The hormonal effects cause diabetes (excess sugar in the blood) with thirst and excess urine; fatigue and failure to grow through puberty are common, too. What are the causes? Acquired haemochromatosis This usually occurs due to accumulated iron from frequent blood transfusions given to treat haemolytic anaemias; it can also arise from excess administration of oral iron and occasionally spontaneously in hereditary anaemias, especially when red blood cells are prematurely being broken up by the body. Frequent transfusions are necessary for children with anaemias, and therefore iron overload affects them easily. Genetic haemochromatosis This is an inherited condition. Excess absorption of iron from the diet persists despite normal or high body iron stores. Over 90 per cent of patients have two copies of the C282Y mutation in the HFE gene on chromosome 6 – a few patients have mutations in the transferrin-receptor gene type 2 and those with mild disease have changes in the ferroportin gene. In patients with rapid-onset and severe disease, different mutations occur in the hepcidin and haemojuvelin genes. How is it diagnosed? Initial detection of iron overload is by blood tests to identify transferrin saturation and ferritin. For genetic haemochromatosis, mutation analysis for the C282Y HFE mutation identifies those patients affected. More sophisticated studies are required to find the other genetic forms. How is it treated? Acquired haemochromatosis This type of haemochromatosis is treated, and indeed prevented, by the use of iron chelation therapy, using a drug such as desferrioxamine given by injection or infusion, or oral agents such as Exjade and deferriprone. These bind iron in the body and allow it to be excreted in the urine and faeces. Genetic haemochromatosis Early diagnosis and treatment by venesection is important to reduce disease progression. Venesection therapy is the taking of approximately one pint of blood, usually every week, until iron levels return to normal. Subsequently venesection continues at a less frequent rate (three to six monthly) for life to prevent iron accumulation. Juvenile disease may require heart transplantation, hormone supplements including insulin for diabetes – and combined agents to prevent the rapid loading of iron. Inheritance patterns and prenatal diagnosis Inheritance patternsGenetic haemochromatosis is inherited in an autosomal recessive manner. Prenatal diagnosisPrenatal diagnosis for the genetic form is not currently used. Is there support? Haemochromatosis Society Tel: 020 8449 1363Email: firstname.lastname@example.orgWebsite: haemochromatosis.org.uk The Society is a Registered Charity in England and Wales No. 1001307. It provides information and support to individuals and families affected by haemochromatosis. The Society promotes greater knowledge of the condition among medical professionals and the public, and supports research. Group details last updated December 2014.