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Hereditary Hemochromatosis
  Am I at Risk?
what is hemochromatosis

By Amanda Ewart Toland, PhD

Reviewed by Chris Friedrich, MD, PhD



Hereditary hemochromatosis is caused by inheriting an alteration, or mutation, in a gene that causes the body to store too much iron. When one member of a family has been diagnosed with hereditary hemochromatosis other family members are also at increased risk for the disorder.

 
 
 

Hemochromatosis Risk in the Family

Your risk of developing hemochromatosis increases with the number of diagnoses in a family and the closeness of the relations. Keep in mind, however, that an individual can have two mutated copies of the most common gene known to cause hemochromatosis, the HFE gene, without ever developing any symptoms of (or complications from) hemochromatosis. Thus, even though the fact that both your parents have been diagnosed with hereditary hemochromatosis guarantees that you have inherited two mutated genes, it doesn't mean that you will develop symptoms or get sick — especially if you and your doctor are aware of and take steps to regulate your own iron levels.

Family Members Diagnosed with Hereditary Hemochromatosis Your Chances of Inheriting Two Mutated Copies of a Gene that Causes Hereditary Hemochromatosis
None (general population) 1 in 200 (0.5 percent)
Aunt, uncle, or cousin Less than 1 in 20 (less than 5 percent)
One parent but no sibling 1 in 20 (5 percent)
Sibling but no parent 1 in 4 (25 percent)
Sibling and parent 1 in 2 (50 percent)
Two parents 1 in 1 (100 percent)

what is hemochromatosistop

 

Looking for Clues of Hemochromtosis

Since many of the early symptoms of hemochromatosis are nonspecific (for example, weakness and fatigue, loss of sex drive, achy muscles) and the more advanced symptoms often mimic other adult-onset disorders (such as diabetes and heart disease), hereditary hemochromatosis often goes undiagnosed in families. Some clues that members of your family may have had undiagnosed hemochromatosis and that you are at risk as well include the following, all of which are complications that can arise from untreated hemochromatosis:

  • Unexplained diabetes
  • Unexplained heart failure
  • Unexplained liver cirrhosis
  • Arthritis
  • Impotence

Also be aware that family members can be carriers of the disorder that is, they have a mutation in one of their two copies of the HFE gene without exhibiting any effects or symptoms of the disorder themselves. Thus, even in the absence of a family history of hemochromatosis, you should have your doctor give you a screening test for the disorder if you experience any of the following symptoms:

  • Weakness or fatigue
  • Decreased sex drive or impotence
  • Abdominal pain
  • Cardiac problems (including abnormal heart rhythms or congestive heart failure
  • Pain in the joints of the fingers

The bottom line is that if anyone in your family has been diagnosed with hemochromatosis (or shows signs of being a carrier), or if you have any unexplained symptoms yourself, you should be tested for the disorder via laboratory studies of iron storage levels and genetic testing, if necessary, to confirm those findings.

what is hemochromatosistop

 

Hemochromatosis Risk and Ethnicity

Individuals of European descent are much more likely to be carriers of what was until recently the only known gene to cause hereditary hemochromatosis, called HFE, than are people of other ethnic ancestries. However, iron overload is just as common in people of African or Mexican descent as it is among Caucasians. Mutations in the HFE gene do not appear to cause hemochromatosis in non-Caucasian populations. Hemochromatosis in these populations may be caused by mutations in a recently described gene, called the transferrin receptor-2 (tfr2), which may be involved in regulation of iron uptake by cells. Genetic testing is not yet commercially available for the tfr2 gene, so if you are not of European descent and suspect that you might have hemochromatosis, your doctor will most likely make a diagnosis based on the nongenetic screening tests.

More on Hemochromatosis Screening and Prevention (Coming Soon)

Ancestry Percentage of Individuals Who Are HFE Mutation Carriers (C282Y allele) Percentage of Individuals Who Are HFE Mutation Carriers (H63D allele)
Northern European 11% 16%
Southern and Eastern European ~1% 10% to 15%
Asian 0% 1% to 10%
African 0% <1%
Pacific Islander/Native American Figures not available Figures not available

what is hemochromatosistop

 

References

Adams, PC. (2000). Nonexpressing homozygotes for C282Y Hemochromatosis: Minority or majority of cases. Mol. Genet. And Metab. 71: 81-86.

Camaschella, C. et al. (2000). The gene TFR2 is mutated in a new type of haemochromatosis mapping to 7q22. Nat. Genet. 25: 14-15.

Olynyk, J.K. et al. (1999). A population-based study of the clinical expression of the hemochromatosis gene. New Engl. J. Med. 341: 718-724 .

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