What Causes Hemochromatosis?
There are two types of hemochromatosis: primary
(hereditary) and secondary. Each type has a different cause.
Primary Hemochromatosis
A defect in the genes that control how much iron you
absorb from your diet causes primary hemochromatosis. Primary hemochromatosis
is sometimes called hereditary hemochromatosis or classical hemochromatosis.
Most cases of hemochromatosis are primary hemochromatosis.
The genes most commonly involved in primary
hemochromatosis are called HFE genes. Abnormal HFE genes cause the body to
absorb too much iron. Humans inherit two copies of most of the genes in the
body, one from each parent. You have primary hemochromatosis if you inherit two
copies of the abnormal HFE gene, one from each parent.
If you inherit one abnormal HFE gene and one normal
HFE gene, you are a hemochromatosis "carrier." Carriers do not usually develop
the disease, but they can pass the abnormal gene on to their children. About 1
in 10 people in the United States are believed to be hemochromatosis
carriers.
If both parents are carriers of the abnormal HFE
gene, then each of their children has a 1 in 4 chance of inheriting a pair of
abnormal HFE genes.
Other types of abnormal genes also can cause
hemochromatosis, but less commonly. Scientists are still studying what other
changes to normal genes may cause hemochromatosis.
Secondary Hemochromatosis
This type of hemochromatosis is usually the result
of another disease or condition that can cause iron overload. Diseases or
conditions that may cause hemochromatosis include:
- Certain anemias, such as
thalassemia
and
aplastic
anemia
- A condition called African iron overload, which
is a combination of an inherited disorder and diet
- Atransferrinemia and aceruloplasminemia, both
rare inherited diseases
- Chronic liver disease, such as hepatitis,
alcoholic liver disease, or nonalcoholic steatohepatitis ("steato" means
"fatty")
Secondary hemochromatosis can sometimes be caused by
too much iron from:
- Blood transfusions
- Iron intake (from oral iron pills or injected
iron)
- Long-term kidney dialysis
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