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    Prothrombin Thrombophilia

    Subjects: Genetics
    View times: 3
    Submitted by: Nora Tang
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    Prothrombin thrombophilia is an inherited disorder of blood clotting. Thrombophilia is an increased tendency to form abnormal blood clots in blood vessels.

    1. Introduction

    People who have prothrombin thrombophilia are at somewhat higher than average risk for a type of clot called a deep venous thrombosis, which typically occurs in the deep veins of the legs. Affected people also have an increased risk of developing a pulmonary embolism, which is a clot that travels through the bloodstream and lodges in the lungs. Most people with prothrombin thrombophilia never develop abnormal blood clots, however. Some research suggests that prothrombin thrombophilia is associated with a somewhat increased risk of pregnancy loss (miscarriage) and may also increase the risk of other complications during pregnancy. These complications may include pregnancy-induced high blood pressure (preeclampsia), slow fetal growth, and early separation of the placenta from the uterine wall (placental abruption). It is important to note, however, that most women with prothrombin thrombophilia have normal pregnancies.

    2. Frequency

    Prothrombin thrombophilia is the second most common inherited form of thrombophilia after factor V Leiden thrombophilia. Approximately 1 in 50 people in the white population in the United States and Europe has prothrombin thrombophilia. This condition is less common in other ethnic groups, occurring in less than one percent of African American, Native American, or Asian populations.

    3. Causes

    Prothrombin thrombophilia is caused by a particular mutation in the F2 gene. The F2 gene plays a critical role in the formation of blood clots in response to injury. The protein produced from the F2 gene, prothrombin (also called coagulation factor II), is the precursor to a protein called thrombin that initiates a series of chemical reactions in order to form a blood clot. The particular mutation that causes prothrombin thrombophilia results in an overactive F2 gene that causes too much prothrombin to be produced. An abundance of prothrombin leads to more thrombin, which promotes the formation of blood clots.

    Other factors also increase the risk of blood clots in people with prothrombin thrombophilia. These factors include increasing age, obesity, trauma, surgery, smoking, the use of oral contraceptives (birth control pills) or hormone replacement therapy, and pregnancy. The combination of prothrombin thrombophilia and mutations in other genes involved in blood clotting can also influence risk.

    The Gene Associated with Prothrombin Thrombophilia

    • F2

    4. Inheritance

    The risk of developing an abnormal clot in a blood vessel depends on whether a person inherits one or two copies of the F2 gene mutation that causes prothrombin thrombophilia. In the general population, the risk of developing an abnormal blood clot is about 1 in 1,000 people per year. Inheriting one copy of the F2 gene mutation increases that risk to 2 to 3 in 1,000. People who inherit two copies of the mutation, one from each parent, may have a risk as high as 20 in 1,000.

    5. Other Names for This Condition

    • hyperprothrombinemia

    • Prothrombin G20210A Thrombophilia

    The entry is from https://medlineplus.gov/genetics/condition/prothrombin-thrombophilia

    References

    1. Bosler D, Mattson J, Crisan D. Phenotypic Heterogeneity in Patients withHomozygous Prothrombin 20210AA Genotype. A paper from the 2005 William BeaumontHospital Symposium on Molecular Pathology. J Mol Diagn. 2006 Sep;8(4):420-5.Review.
    2. McGlennen RC, Key NS. Clinical and laboratory management of the prothrombinG20210A mutation. Arch Pathol Lab Med. 2002 Nov;126(11):1319-25. Review.
    3. Spector EB, Grody WW, Matteson CJ, Palomaki GE, Bellissimo DB, Wolff DJ,Bradley LA, Prior TW, Feldman G, Popovich BW, Watson MS, Richards CS. Technicalstandards and guidelines: venous thromboembolism (Factor V Leiden and prothrombin20210G >A testing): a disease-specific supplement to the standards and guidelinesfor clinical genetics laboratories. Genet Med. 2005 Jul-Aug;7(6):444-53.
    4. Varga EA, Moll S. Cardiology patient pages. Prothrombin 20210 mutation (factorII mutation). Circulation. 2004 Jul 20;110(3):e15-8.
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