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Genetics of Hereditary Hemochromatosis

written by: R. Elizabeth C. Kitchen•edited by: Emma Lloyd•updated: 6/27/2010

Have you been affected by this genetic disorder? If so, read on to learn more about this disorder and the genetics of hereditary hemochromatosis.

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    Hereditary hemochromatosis is a genetic disorder and is quite common in the United States. Knowing the genetics of hereditary hemochromatosis allows both doctors and patients to better understand this disease, therefore, they can better treat it.

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    What is Hereditary Hemochromatosis and How Does it Affect the Body?

    This genetic disorder is characterized by iron overload, or iron accumulating excessively in the body. Some patients will not experience any symptoms and some will experience severe symptoms. The early stage symptoms can include:

    • Arthritis, specifically affecting the hands
    • Impotence or loss of libido
    • Abdominal pain
    • Low thyroid function
    • Chronic fatigue
    • Lack of normal menstruation
    • High blood sugar levels
    • Abnormal liver function tests (this can occur with or without other symptoms being present)

    Advanced stage symptoms include:

    • Cirrhosis
    • Liver cancer
    • Congestive heart failure
    • Discolored skin that is gray or bronze looking
    • Liver failure
    • Diabetes
    • Cardiac arrhythmia

    genetics of hereditary hemochromatosis Normal body levels of iron is three to four grams. The body naturally uses and replaces iron and keeps it at about three to four grams consistently. In patients with this genetic disorder, the intestines absorb far more iron than it needs to to replace the iron the body naturally uses on a day to day basis. A normal body cannot increase how much iron it secretes, the body absorbs the excess iron and it accumulates.

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    How Common is This Condition?

    About every one in every 240 to 300 Caucasians are affected by hereditary hemochromatosis. Approximately one-million people in the United States have the type one type of this disorder, making it one of the most prevalent genetic disorders diagnosed in the United States. Those of Northern European descent are the most commonly affected. The other types of this disorder are rare and only found in a small amount of families throughout the world.

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    Genetics of Hereditary Hemochromatosis

    Understanding the genetics of hereditary hemochromatosis allow us to understand the genes associated with this disorder, as well as its inheritance pattern. Mutations in the HFE, SLC40A1, HAMP, TFR2, and HFE2 genes cause this genetic disorder. These genes have an integral role in regulating the transport, absorption, and storage of iron. When these genes are mutated, it affects how they control iron absorption during the digestive process and a mutation alters iron distribution throughout the other areas of the body. This disorder is inherited in an autosomal recessive pattern. Type 4 hereditary hemochromatosis is inherited in an autosomal dominant pattern. The neonatal hemochromatosis inheritance pattern is unknown.

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    How is Hereditary Hemochromatosis Treated?

    Hereditary hemochromatosis can be effectively and safely treated for most patients. It is treated through blood removal which helps to decrease blood-iron levels and keep them at a normal level. Patients may first begin treatment by giving a pint of blood one to two times a week. Each course, takes approximately thirty minutes. Once iron levels are normalized, patients will need to undergo blood removal four to six times a year in order to maintain normal blood-iron levels. After giving blood patients may feel tired, dizzy, or faint. However, the doctors and/or nurses taking care of the blood removal will ensure the patient is safe and feels as good as possible.

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    Resources

    Mayo Clinic. (2008). Hemochromatosis. Retrieved on June 20, 2010 from the Mayo Clinic: http://www.mayoclinic.com/health/hemochromatosis/DS00455

    Genetics Home Reference. (2010). Hemochromatosis. Retrieved on June 20, 2010 from Genetics Home Reference: http://ghr.nlm.nih.gov/condition=hemochromatosis

    Medicine Net. (2010). Hereditary Hemochromatosis. Retrieved on June 20, 2010 from Medicine Net: http://www.medicinenet.com/iron_overload/article.htm

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    Image Credits

    Blood: easy37 – sxc.hu