There are two types of hemochromatosis:
- Hereditary hemochromatosis
- Acquired hemochromatosis.
Causes of Hereditary Hemochromatosis
The gene that causes hereditary hemochromatosis, called the HFE gene, was identified on chromosome 6 in 1996. A child who inherits two copies of a mutated HFE gene (one from each parent) is highly likely to develop hemochromatosis. However, not all people who have two mutated copies develop signs and symptoms of hemochromatosis.
People who inherit only one copy of the mutated HFE gene are hemochromatosis carriers, but usually have no related symptoms, or only have mild symptoms, since one correct copy of the gene appears to adequately regulate iron absorption. "Silent" carriers, without symptoms, can still pass on the defect to their children.
If two parents are silent carriers, a child has a 25 percent chance of inheriting two copies of the defective gene, and will most likely develop the disease. An estimated 10 percent of the U.S. population carries this gene. Carriers are most likely to exhibit signs of hemochromatosis if there are triggers such as diabetes or alcoholism.
Causes of Acquired Hemochromatosis
Acquired hemochromatosis is caused by other medical conditions -- in particular, those in which there is a problem making red blood cells or hemoglobin. Medical conditions that can result in hemochromatosis include:
- Sideroblastic anemia
- Porphyria cutanea tarda
- Alcoholics with chronic liver disease
- Excessive iron intake
- Frequent blood transfusions
- Myelodysplastic syndrome
- Sickle cell anemia
- Hepatitis C.
(Click Causes of Hemochromatosis for more information.)