Causes

Hereditary hemochromatosis is caused by a mutation in a gene that controls the amount of iron your body absorbs from the food you eat. These mutations are passed from parents to children. This type of hemochromatosis is by far the most common type.

Gene mutations that cause hemochromatosis

A gene called HFE is most often the cause of hereditary hemochromatosis. You inherit one HFE gene from each of your parents. The HFE gene has two common mutations, C282Y and H63D. Genetic testing can reveal whether you have these mutations in your HFE gene.

• If you inherit 2 abnormal genes, you may develop hemochromatosis. You can also pass the mutation on to your children. But not everyone who inherits two genes develops problems linked to the iron overload of hemochromatosis.
• If you inherit 1 abnormal gene, you're unlikely to develop hemochromatosis. However, you are considered a gene mutation carrier and can pass the mutation on to your children. But your children wouldn't develop the disease unless they also inherited another abnormal gene from the other parent.

How hemochromatosis affects your organs

Iron plays an essential role in several body functions, including helping in the formation of blood. But too much iron is toxic.

A hormone called hepcidin, secreted by the liver, normally controls how iron is used and absorbed in the body, as well as how excess iron is stored in various organs. In hemochromatosis, the normal role of hepcidin is disrupted, causing your body to absorb more iron than it needs.

This excess iron is stored in major organs, especially your liver. Over a period of years, the stored iron can cause severe damage that may lead to organ failure and chronic diseases, such as cirrhosis, diabetes and heart failure. Though many people have faulty genes that cause hemochromatosis, not everyone develops iron overload to a degree that causes tissue and organ damage.

Hereditary hemochromatosis isn't the only type of hemochromatosis. Other types include:

• Juvenile hemochromatosis. This causes the same problems in young people that hereditary hemochromatosis causes in adults. But iron accumulation begins much earlier, and symptoms usually appear between the ages of 15 and 30. This disorder is caused by mutations in the hemojuvelin or hepcidin genes.
• Neonatal hemochromatosis. In this severe disorder, iron builds up rapidly in the liver of the developing baby in the womb. It is thought to be an autoimmune disease, in which the body attacks itself.
• Secondary hemochromatosis. This form of the disease is not inherited and is often referred to as iron overload. People with certain types of anemia or chronic liver disease may need multiple blood transfusions, which can lead to excess iron accumulation.