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Genetic and Rare Diseases Information Center (GARD)

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Prothrombin thrombophilia


Other Names for this Disease

  • Factor II-related thrombophilia
  • Hyperprothrombinemia
  • Prothrombin 20210G>A thrombophilia
  • Prothrombin G20210A thrombophilia
  • Prothrombin-related thrombophilia
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Overview

What is prothrombin thrombophilia?

What are the signs and symptoms of prothrombin thrombophilia?

How is prothrombin thrombophilia inherited?

What is prothrombin thrombophilia?

Prothrombin thrombophilia is an inherited disorder of blood clotting. Thrombophilia is an increased tendency to form abnormal blood clots in blood vessels. People who have prothrombin thrombophilia are at somewhat higher than average risk for a type of clot called a deep venous thrombosis, which typically occur in the deep veins of the legs. Affected people also have an increased risk of developing a pulmonary embolism. However, most people with prothrombin thrombophilia never develop abnormal blood clots. Prothrombin thrombophilia is the second most common inherited form of thrombophilia after factor V Leiden thrombophilia. It is more common in Caucasian populations. This condition is caused by a particular mutation (written G20210A or 20210G>A) in the F2 gene. People can inherit one or two copies of the gene mutation from their parents.[1]
Last updated: 12/5/2011

What are the signs and symptoms of prothrombin thrombophilia?

The signs and symptoms of this condition depend on whether a person has inherited one or two copies of the F2 gene mutation from his or her parents. A person who inherits one gene mutation is called a heterozygote. Whereas a person that inherits two gene mutations (one from each parent) is considered a homozygote for this condition; although it is very rare to find individuals who are homozygous. An affected heterozygous person usually experiences mild to moderate increase in their thrombin production, which is associated with 2.5 to 3 fold greater risk of developing a venous thromboembolism. There is not enough information about risk in those who are homozygous.[1]

Some research suggests that in women, 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.[1]
Last updated: 12/5/2011

How is prothrombin thrombophilia inherited?

Prothrombin thrombophilia is inherited in an autosomal dominant manner. For this condition, this means that having one mutated copy of the disease-causing gene (F2) in each cell may be sufficient to cause signs or symptoms of the condition. The mutation in the F2 gene that causes prothrombin thrombophilia is called 20210G>A (also called the 20210G>A allele).[2] An individual can be heterozygous (having the mutation in only one copy of the F2 gene) or homozygous (having a mutation in both copies of the F2 gene). Heterozygosity results in an increased risk for thrombosis; homozygosity results in more severe thrombophilia and/or increased risk for thrombosis.[2]

All individuals reported to date with prothrombin thrombophilia who are heterozygous for the 20210G>A allele have had an affected parent. Because of the relatively high prevalence of this allele in the general population, occasionally one parent is homozygous or both parents are heterozygous for this allele.[2]

When an individual who is heterozygous for the 20210G>A allele has children, each child has a 50% (1 in 2) risk to inherit that allele and also be heterozygous. An individual who is homozygous will always pass one of the 20210G>A alleles to each of his/her children. If two heterozygotes have children together, each child has a 25% (1 in 4) risk to be homozygous (having 2 mutated copies), a 50% risk to be heterozygous like each parent, and a 25% risk to inherit 2 normal copies of the F2 gene.
Last updated: 4/10/2013

References
  1. Prothrombin thrombophilia. Genetics Home Reference. August 2008; http://ghr.nlm.nih.gov/condition/prothrombin-thrombophilia. Accessed 8/8/2011.
  2. Jody L Kujovich. Prothrombin-Related Thrombophilia. GeneReviews. March 29, 2011; http://www.ncbi.nlm.nih.gov/books/NBK1148/. Accessed 4/9/2013.


Other Names for this Disease
  • Factor II-related thrombophilia
  • Hyperprothrombinemia
  • Prothrombin 20210G>A thrombophilia
  • Prothrombin G20210A thrombophilia
  • Prothrombin-related thrombophilia
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.