Hemochromatosis

Hemochromatosis, one of the most common inherited diseases in the United States, is a disorder that causes the body to absorb and store too much iron. The extra iron builds up in organs and damages them. Without treatment, the disease can cause these organs to fail.

Symptoms

Joint pain is the most common complaint of people with hemochromatosis. Other common symptoms include fatigue, lack of energy, abdominal pain, loss of sex drive, and heart problems. Symptoms tend to occur in men between the ages of 30 and 50 and in women over age 50. However, many people have no symptoms when they are diagnosed.

If the disease is not detected early and treated, iron may accumulate in body tissues and may eventually lead to serious problems such as

• arthritis
• liver disease, including an enlarged liver, cirrhosis, cancer, and liver failure
• damage to the pancreas, possibly causing diabetes
• heart abnormalities, such as irregular heart rhythms or congestive heart failure
• impotence
• early menopause
• abnormal pigmentation of the skin, making it look gray or bronze
• thyroid deficiency
• damage to the adrenal gland

Diagnosis

A thorough medical history, a physical examination, and routine blood tests help rule out other conditions that could be causing the symptoms. This information often provides helpful clues, such as a family history of arthritis or unexplained liver disease.

Blood tests can determine whether the amount of iron stored in the body is too high. The transferrin saturation test determines how much iron is bound to the protein that carries iron in the blood. The total iron binding capacity (TIBC) test measures how well your blood can transport iron. The serum ferritin test shows the level of iron in the liver. If either of these tests shows higher than normal levels of iron in the body, doctors can order a special blood test to detect the HFE mutation, which will help confirm the diagnosis. (If the mutation is not present, hereditary hemochromatosis is not the reason for the iron buildup, and the doctor will look for other causes.) A liver biopsy, in which a tiny piece of liver tissue is removed and examined under a microscope, may be needed. It will show how much iron has accumulated in the liver and whether the liver is damaged.

Causes

There are two types of hemochromatosis: primary (hereditary) and secondary. Each type has a different cause.

Primary Hemochromatosis

Primary hemochromatos is caused by a defect in the genes that control iron absorption from diet. It is sometimes called hereditary hemochromatosis or classical hemochromatosis. Most cases of hemochromatosis are primary hemochromatosis.

The gene most commonly involved in primary hemochromatosis is the HFE gene, which helps regulate the amount of iron absorbed from food. Mutations of the gene may cause over-absorption of iron. The genetic defect is present at birth, but symptoms rarely appear before adulthood. A person who inherits the defective gene from both parents may develop hemochromatosis. A person who inherits the defective gene from only one parent is a carrier for the disease but usually does not develop it. However, carriers might have a slight increase in iron absorption.

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

Reference:

National Heart, Lung, and Blood Institute, USA.
National Digestive Diseases Information Clearinghouse, USA.