Iron Overload and Hemochromatosis : Causes, Risks and Diagnosis

by CDC

(Page 2 of 5)

Causes and Risk Factors

In the United States, the most common form of hemochromatosis in adults is called hereditary hemochromatosis or classic hemochromatosis. This form of the disease is caused by a defect in the genes that control how iron is absorbed by the body.

Causes

The amount of iron the human body absorbs is controlled by many genes. Genes can sometimes change (or mutate) in ways that keep them from working properly.

Hereditary hemochromatosis can occur when a person inherits two mutated copies of a gene called the HFE gene - one from each parent. Men and women have the same chance of inheriting two copies of this gene.

Not everyone who is born with two copies of the mutated HFE gene develops the disease. Scientists do not know what percentage of people who have two copies of the mutated HFE gene develop the disease. Some studies have shown that as few as 1 in 100 people will develop symptoms. Other studies have shown that as many as 50 in 100 people may develop symptoms. A person with only one copy of the mutated HFE gene is usually healthy and is said to be a "carrier" of the genetic condition. Although a carrier usually does not have hemochromatosis, if both a mother and father are carriers, a child may inherit two copies of the mutated gene, one from each parent.

Risk Factors

People who inherit the HFE gene mutation from both parents are at the greatest risk for developing hemochromatosis. Although both men and women can inherit the gene defect, men are more likely to be diagnosed with the effects of hemochromatosis than women. Other factors that increase risk are listed in the following table.

Ethnic background

White people of northern European descent (for example, families from England, Ireland, Scotland, Denmark, France, and Scandinavia) have a higher chance of having the HFE gene mutation.

Family history

People with a close relative (grandparent, mother, father, sibling, niece, nephew) who has hemochromatosis have a higher chance of having the HFE gene mutation.

Factors That May Affect Iron Buildup

For people at risk of developing hemochromatosis, the speed at which iron builds up and the severity of the symptoms vary from person to person. Many people do not have any early symptoms. Symptoms tend to occur in men between the ages of 30 and 50 and in women over age 50. The following factors may affect the buildup of iron in the body and may speed up or slow down the development of hemochromatosis.

Use of dietary supplements

Taking iron supplements or multivitamins with iron can speed up the rate at which iron builds up in the body. Persons with hemochromatosis should not take pills containing iron. Eating foods that contain iron is fine.

Taking vitamin C supplements may cause the body to absorb more iron. Persons with hemochromatosis should not take pills with more than 500 milligrams of vitamin C per day. Eating foods that contain vitamin C is fine.

Blood loss

Losing iron by giving blood and losing iron through menstruation and unrecognized bleeding may slow the start of hemochromatosis. Therefore, men at risk for hemochromatosis usually develop the disease and its symptoms at a younger age than women who are at risk.

Key Point

People with the HFE gene mutation may absorb extra iron from their diet each day. Over many years, this extra iron may cause a buildup of iron in the body that can lead to disease. Persons with hemochromatosis should not take pills containing iron.

Detection and Diagnosis

Most regular medical check-ups do not include tests to measure the amount of iron in the body. For that reason, hemochromatosis is often not identified in people who have the disease.

If you think you have symptoms like those of hemochromatosis, (fatigue, weakness, abdominal pain and/or joint pain), or if you have a close relative who has hemochromatosis, you should ask your health care provider to check the amount of iron in your blood.

Early detection of iron buildup is important because prompt diagnosis and treatment of hemochromatosis can help prevent the more serious problems caused by the disease.

To see if you might be at risk for hemochromatosis, a doctor will take a complete medical history and give you a physical examination. Having information about your family's health history is also helpful.

To check the amount of iron in your body, a doctor can use two simple blood tests: Transferrin saturation (TS) test, Serum ferritin (SF) test.

If these tests show that you have too much iron in your body, you will need to start phlebotomy (pronounced "fle-bot-o-me") treatment.

Transferrin Saturation (TS) Test

You should not eat after midnight on the night before your blood is drawn for the transferrin saturation (TS) test.

If, on an empty stomach, your TS value is greater than 45%, you should have a serum ferritin test done.

Note that taking any of the following supplements or pills in the day prior to your blood draw can make TS values higher than normal: Multivitamins with iron, Multivitamins or pills with vitamin C, Medicinal iron.

If you take any of these supplements or pills, you should not use them for 24 hours before blood is drawn for the TS test.

Serum Ferritin (SF) Test

For information about interpreting the serum ferritin (SF) test, see the following table.

For women

If you have not been through menopause, an SF greater more than 200 ng/mL (nanograms per milliliter) means there is too much iron in your body. If you have been through menopause, an SF value greater than 300 ng/mL means there is too much iron in your body.

For men

An SF value greater than 300 ng/mL means there is too much iron in your body.

These blood tests, a thorough medical history, and a physical examination may also help rule out other conditions that could be causing the symptoms.

Key Point

If you think you have symptoms like those of hemochromatosis or if you have a close blood relative who has hemochromatosis, you should ask your health care provider to check the amount of iron in your blood.

About the Author

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The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.