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haemochromatosis Alternative Names
hereditary haemochromatosis, idiopathic haemochromatosis, bronze diabetes, iron overload disease
Definition
Haemochromatosis is a genetic disorder that affects the way the body handles iron. It causes iron to accumulate in the organs of affected people. The excessive iron causes the symptoms of the disorder.
What is going on in the body?
Everyone absorbs iron from the food they eat. In a person with haemochromatosis, too much iron is absorbed. The iron accumulates in organs such as the liver, heart, and pancreas. The overload of iron causes liver disease, congestive heart failure, and diabetes.
What are the signs and symptoms of the disease?
Haemochromatosis is characterised by: - too much iron in the blood
- darkening of the skin
- cirrhosis of the liver. This condition involves changes in the liver in response to damage by excessive iron.
- increased chance of developing liver cancer
- enlargement of the heart
- high blood sugar, caused by diabetes
What are the causes and risks of the disease?
Haemochromatosis is caused by a defective gene. The gene for haemocromatosis is recessive. This means a person must have two copies of this gene to have the disease. People with a single copy of the gene are called carriers. Carriers usually are not affected, although use of alcohol may cause symptoms to appear in them.
In the general population at least one in 300 people are likely to be affected by haemochromatosis during his or her lifetime.
What can be done to prevent the disease?
Nothing can be done to prevent the defect in iron handling that leads to haemochromatosis. The symptoms can be avoided or minimised by removing blood at regular intervals. Affected people and carriers of the gene should avoid use of alcohol and steroid medications.
Genetic counselling may be useful for couples with a family history of the disease.
How is the disease diagnosed?
Haemochromatosis is diagnosed by measuring the amount of iron in the blood. There are several blood tests that can do this: - serum ferritin, which measures the protein that acts as a carrier for iron in the blood stream
- serum iron, which measures iron concentrations in the blood
- total iron-binding capacity, or TIBC, which measures the amount of iron that can potentially be stored in the blood
The level of iron compounds in the urine may also be measured. Also, a liver biopsy may be done to obtain tissue for examination in the laboratory. Now that the gene that causes haemochromatosis has been identified, however, DNA testing to examine a person's genes may be done to diagnose the disease.
What are the long-term effects of the disease?
Iron overload in a person with haemochromatosis probably starts at birth. The symptoms usually are not obvious, however, until middle life. As the disorder progresses it leads to: What are the risks to others?
Haemochromatosis is not contagious. Parents who have had an affected child are at risk of having other affected children. Because the symptoms come on later in life, affected parents often do not know there is a risk until after their reproductive years. A person with haemochromatosis will pass on defective genes to his or her children. The children will not be affected unless the other parent is affected or carries the gene. However, they will be carriers of the gene. Genetic counselling can be useful in providing additional information for family members.
What are the treatments for the disease?
The most effective treatment for haemochromatosis is to remove blood that is saturated by iron. This can be done through simple blood drawing techniques. After the blood is withdrawn, the body makes more blood that is not saturated by iron. Over time the newly formed blood becomes saturated and must also be withdrawn. When haemochromatosis is first recognised, the blood may have to be withdrawn every couple of weeks for 2 to 3 years. Thereafter, it may be withdrawn a couple of times a year. The blood that is withdrawn usually is discarded.
If removal of saturated blood is not possible, chelation therapy can be used to bind the iron and excrete it in the urine. Deferoxamine injections, for example, bind up iron and remove it from the bloodstream. Chelation therapy does not remove nearly as much iron as removing blood from the body. That is why frequent blood draws are the preferred treatment, if at all possible.
If organ damage has already taken place, the resulting conditions such as diabetes, erectile dysfunction, congestive heart failure, and cirrhosis must be treated.
What are the side effects of the treatments?
If only small amounts of blood are withdrawn, there are no side effects of treatment. If too much blood is removed, symptoms of anaemia can occur. These can include fatigue, weakness, and shortness of breath. Deferoxamine can cause allergic reactions, skin rash, and diarrhoea.
What happens after treatment for the disease?
Treatment for haemochromatosis is a life long process. If treatment is stopped, the blood becomes saturated by iron and symptoms will reappear.
How is the disease monitored?
Haemochromatosis is monitored by checking the level of ferritin every several months.
Author: Ronald J. Jorgenson, DDS, PhD, FACMG
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Contributors
Potential conflict of interest information for reviewers available on request |
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