What Is Hereditary Hemochromatosis?
Hereditary hemochromatosis is a disorder that causes the body to absorb too much iron. This causes iron to build up in the blood, liver, heart, pancreas, joints, skin, and other organs.
In its early stages, hemochromatosis can cause joint and belly pain, weakness, lack of energy, and weight loss. It can also cause scarring of the liver (cirrhosis), darkening of the skin, diabetes, infertility, heart failure, irregular heartbeats (arrhythmia), and arthritis. But many people do not have symptoms in the early stages.
In men, hereditary hemochromatosis is usually found at ages 40 to 60. In women, it is not usually found until after menopause because, until that time, women regularly lose blood and iron during their monthly periods.
What Causes Hereditary Hemochromatosis?
Hereditary hemochromatosis is a genetic disorder called an autosomal recessive disorder. It is passed from a parent to a child (inherited). Most people who have hemochromatosis inherit defective genes from both parents. In rare cases, a person can have hemochromatosis by inheriting defective genes from just one parent.
A person who has inherited only one defective gene will most likely be a carrier of hemochromatosis and will not have the disease. A carrier can pass the defective gene on to his or her children.
- If only one parent is a carrier of a defective gene, the child will not have hemochromatosis. But there is a 50% chance that the child will be a carrier.
- If both parents are carriers, there is only a 25% chance that the child will have both defective genes and so will have a higher risk of getting hemochromatosis. But there is a 50% chance that the child will be a carrier.
What Is Hemochromatosis Genetic (HFE) Screening?
Screening tests help your doctor look for a certain disease or condition before any symptoms appear. This can increase your chance of finding the problem at a curable or more treatable stage.
Hemochromatosis gene (HFE) testing is done to check to see if a person is likely to develop hereditary hemochromatosis. This test checks whether you are a carrier of the defective gene that causes hemochromatosis. HFE testing locates gene mutations that are called C282Y and H63D. The test can usually confirm whether a person has an increased chance for having hereditary hemochromatosis.
HFE testing identifies a genetic risk rather than the disease itself. Even if you have one or more HFE gene mutations, you may never get sick.
Who Should Be Screened?
Screening is only recommended for people who have an increased chance of having the disease, such as those with other family members who have hereditary hemochromatosis. The test may be ordered if you have a close family member—parent, brother, sister, or child—with the condition. It is best to get tested when you are age 18 to 30 when tests can usually detect the disease before serious organ damage occurs.
Genetic counselling to help you understand the meaning and possible results of the test is recommended before having genetic testing.
In the United States, the U.S. Preventive Services Task Force (USPSTF) does not recommend genetic screening for hemochromatosis in the general population.footnote 1 Screening is not recommended for the general population because hemochromatosis is not common. The general population includes people who do not have symptoms of hemochromatosis and who do not have a parent, brother, sister, or child with the disease.
Anyone can have the test, but a doctor must order it. You may decide to have HFE testing if other people in your family have hereditary hemochromatosis and:
- You want to see if you have the gene mutation too.
- You want to see how likely it will be that you will pass the disease on to your children.
Is Screening Accurate?
The HFE screening test is very accurate in finding the common mutations in the HFE gene. But only about 85% of hemochromatosis is caused by the mutations found by the HFE screening.footnote 2, footnote 3 Even if you have HFE mutations, you may not have the disease. Or, you may have the disease, but gene testing did not find the mutations that are causing the disease.
Should I Be Screened?
The decision to have hereditary hemochromatosis carrier screening is a personal one.
This testing is used to find out if a person has an increased chance for having hemochromatosis. It may be recommended for people who have a close family member—parent, brother, sister, or child—with this disease.
If you are thinking about having genetic testing, talk with your doctor about the benefits as well as the possibility of insurance, employment, or other discrimination based on test results. An HFE test result is private information.
Why Not Be Screened?
There may be reasons you would choose not to have carrier testing.
- You think that your risk of being a carrier is low. This may be true if you are of African or Asian descent. Fewer people in these groups have hereditary hemochromatosis.
- Carrier testing is expensive. You may decide not to have testing if your insurance does not pay for it.
- You may worry that test results could affect your future employment options or the cost or availability of private health insurance, life insurance, disability insurance, or long-term care insurance. For more information on the risks of genetic discrimination in Canada, talk with your doctor or contact the Canadian Coalition for Genetic Fairness at 1-800-998-7398. Or visit its website at www.ccgf-cceg.ca.
- Testing is not always able to predict if you will have hereditary hemochromatosis. Although the test detects the most common hemochromatosis gene (HFE) mutations, there may be other HFE mutations that the test does not detect. There is a small chance that you are a carrier even if the results are normal because there may be other HFE mutations that the test does not find. HFE gene testing is usually not used to check for other, less common causes of inherited hemochromatosis.
- U.S. Preventive Services Task Force (2006). Screening for hemochromatosis. Available online: http://www.ahrq.gov/clinic/uspstf06/hemochromatosis/hemochrs.htm.
- Bacon BR (2015). Cirrhosis and its complications. In DL Kasper et al., eds., Harrison's Principles of Internal Medicine, 19th ed., vol. 2, pp. 2058–2067. New York: McGraw-Hill Education.
- National Human Genome Research Institute (2010). Learning about hereditary hemochromatosis. Available online: http://www.genome.gov/page.cfm?pageID=10001214.
Current as ofMay 6, 2018
Author: Healthwise Staff
Medical Review: Kathleen Romito, MD - Family Medicine
Brian O'Brien, MD, FRCPC - Internal Medicine
E. Gregory Thompson, MD - Internal Medicine
Adam Husney, MD - Family Medicine
Martin J. Gabica, MD - Family Medicine
Elizabeth T. Russo, MD - Internal Medicine
Brian Leber, MDCM, FRCPC - Hematology
Current as of: May 6, 2018
Author: Healthwise Staff
Medical Review:Kathleen Romito, MD - Family Medicine & Brian O'Brien, MD, FRCPC - Internal Medicine & E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & Elizabeth T. Russo, MD - Internal Medicine & Brian Leber, MDCM, FRCPC - Hematology