Author: Vanessa Ngan, Staff Writer, 2005.
Haemochromatosis is also known as ‘bronze diabetes’.
Haemochromatosis is a genetic disorder that causes the body to absorb excessive amounts of iron from the diet. Excess iron is normally metabolised and excreted from the body but in haemochromatosis, excess iron is deposited in organs, mainly the liver, but also the pancreas, heart, endocrine glands and joints. The liver becomes enlarged and damaged and other organs and joints may also be damaged.
Haemochromatosis is characterised by the four main features; cirrhosis of the liver, diabetes mellitus, increased skin pigmentation and heart failure. The condition is ten times commoner in males than in females and usually presents at between 40 and 60 years of age.
Patients with haemochromatosis may develop one or more of the above symptoms over a period of time as iron slowly accumulates and deposits in organs. Often the disease is not diagnosed until routine blood tests show elevated blood iron levels. Patients often seek help because of tiredness, abdominal discomfort, joint pains, and general malaise experienced over a prolonged period of time.
Haemochromatosis is caused by mutations in the HFE gene that is inherited in an autosomal recessive manner. Two mutations identified in the HFE gene are C282Y and H63D. For an individual to have haemochromatosis they must have inherited a defective gene from each parent. A person who has one defective gene and one normal gene is termed a “carrier” and will lead a perfectly healthy life. However, the carrier is able to pass on the defective gene to a son or daughter. Furthermore, up to half of all patients with porphyria cutanea tarda carry at least one HFE gene mutation and this may contribute to the increased stores of liver iron seen in these patients. Haemochromatosis is the most common single-gene inherited disorder in whites, with one in ten persons carrying one abnormal gene.
Several tests can be done to confirm the diagnosis of haemochromatosis. Laboratory studies show elevated levels of iron in the blood and body stores. serum iron concentrations greater than 150 mcg/dL and serum ferritin levels greater than 500 ng/mL. 92% of patients have transferrin saturation greater than 62%. X-rays may show an enlarged heart and blood tests may show liver disease or diabetes, increased blood vessels in the lungs and restrictive cardiomyopathy on echocardiograms.
Genetic tests for the C282Y and H63D mutations are widely available. These tests can be performed to confirm diagnosis or as a screening mechanism for early detection of at risk individuals.
Treatment of haemochromatosis consists of regular removal of blood. This procedure is known as venesection therapy or phlebotomy and is similar to making a blood donation. Every pint of blood removed contains a quarter of a gram of iron. Depending on the amount of iron overload the procedure may initially be performed once weekly or once monthly. This regularity of treatment continues until serum ferritin levels (an indication of body iron stores) fall back to normal; this may take up to 2 years or more. After this, lifelong maintenance therapy needs to be set in place as excess iron continues to be absorbed. On average venesection is required every 3-4 months to prevent build-up and maintain normal levels. Regular monitoring of serum ferritin, transferrin saturation, haematocrit and haemoglobin is necessary throughout the treatment process.
It is important to detect haemochromatosis as early as possible so that venesection can be instituted to prevent the build up of iron and potential complications. Once complications such as diabetes and cirrhosis have developed they cannot be reversed. Tiredness, and abdominal pain should diminish, and increased pigmentation of the skin should fade over time once treatment has been started. Arthritis, however, may fail to improve with venesection.
Haemochromatosis cannot be treated with a low iron diet. However, some foods affect the way the body absorbs iron. The following dietary tips may play a small part in reducing the symptoms of the disease.
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