Question: What causes Hemochromatosis ?
Answer: Primary Hemochromatosis
Inherited genetic defects cause primary hemochromatosis, and mutations in the HFE gene are associated with up to 90 percent of cases.1 The HFE gene helps regulate the amount of iron absorbed from food. The two known mutations of HFE are C282Y and H63D. C282Y defects are the most common cause of primary hemochromatosis.
People inherit two copies of the HFE geneone copy from each parent. Most people who inherit two copies of the HFE gene with the C282Y defect will have higher-than-average iron absorption. However, not all of these people will develop health problems associated with hemochromatosis. One recent study found that 31 percent of people with two copies of the C282Y defect developed health problems by their early fifties.2 Men who develop health problems from HFE defects typically develop them after age 40.1 Women who develop health problems from HFE defects typically develop them after menopause.1
People who inherit two H63D defects or one C282Y and one H63D defect may have higher-than-average iron absorption.3 However, they are unlikely to develop iron overload and organ damage.
Rare defects in other genes may also cause primary hemochromatosis. Mutations in the hemojuvelin or hepcidin genes cause juvenile hemochromatosis, a type of primary hemochromatosis. People with juvenile hemochromatosis typically develop severe iron overload and liver and heart damage between ages 15 and 30.
Secondary Hemochromatosis
Hemochromatosis that is not inherited is called secondary hemochromatosis. The most common cause of secondary hemochromatosis is frequent blood transfusions in people with severe anemia. Anemia is a condition in which red blood cells are fewer or smaller than normal, which means they carry less oxygen to the bodys cells. Types of anemia that may require frequent blood transfusions include
- congenital, or inherited, anemias such as sickle cell disease, thalassemia, and Fanconis syndrome - severe acquired anemias, which are not inherited, such as aplastic anemia and autoimmune hemolytic anemia
Liver diseasessuch as alcoholic liver disease, nonalcoholic steatohepatitis, and chronic hepatitis C infectionmay cause mild iron overload. However, this iron overload causes much less liver damage than the underlying liver disease causes.
Neonatal Hemochromatosis
Neonatal hemochromatosis is a rare disease characterized by liver failure and death in fetuses and newborns. Researchers are studying the causes of neonatal hemochromatosis and believe more than one factor may lead to the disease.
Experts previously considered neonatal hemochromatosis a type of primary hemochromatosis. However, recent studies suggest genetic defects that increase iron absorption do not cause this disease. Instead, the mothers immune system may produce antibodiesproteins made by the immune system to protect the body from foreign substances such as bacteria or virusesthat damage the liver of the fetus. Women who have had one child with neonatal hemochromatosis are at risk for having more children with the disease.4 Treating these women during pregnancy with intravenous (IV) immunoglobulina solution of antibodies from healthy peoplecan prevent fetal liver damage.4
Researchers supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recently found that a combination of exchange transfusionremoving blood and replacing it with donor bloodand IV immunoglobulin is an effective treatment for babies born with neonatal hemochromatosis.5