The two types of hemochromatosis are primary and secondary. Each type has a different cause.
Primary hemochromatosis is caused by a defect in the genes that control how much iron you absorb from food. This form of the disease sometimes is called hereditary or classical hemochromatosis. Primary hemochromatosis is more common than the secondary form of the disease.
The genes usually involved in primary hemochromatosis are called HFE genes. Faulty HFE genes cause the body to absorb too much iron. If you inherit two copies of the faulty HFE gene (one from each parent), you're at risk for iron overload and signs and symptoms of hemochromatosis.
If you inherit one faulty HFE gene and one normal HFE gene, you're a hemochromatosis "carrier." Carriers usually don't develop the disease. However, they can pass the faulty gene on to their children. Estimates suggest that about 1 in 10 people in the United States are hemochromatosis carriers.
If two parents are carriers of the faulty HFE gene, then each of their children has a 1 in 4 chance of inheriting two faulty HFE genes.
Although less common, other faulty genes also can cause hemochromatosis. Researchers continue to study what changes to normal genes may cause the disease.
Secondary hemochromatosis usually is the result of another disease or condition that causes iron overload. Examples of such diseases and conditions include:
- Certain types of anemia, such as thalassemias and sideroblastic anemia
- Atransferrinemia and aceruloplasminemia—both are rare, inherited diseases
- Chronic liver diseases, such as chronic hepatitis C infection, alcoholic liver disease, or nonalcoholic steatohepatitis
Other factors also can cause secondary hemochromatosis, including:
- Blood transfusions
- Oral iron pills or iron injections, with or without very high vitamin C intake (vitamin C helps your body absorb iron)
- Long-term kidney dialysis