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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

Prothrombin deficiency

Reviewed November 2013

What is prothrombin deficiency?

Prothrombin deficiency is a bleeding disorder that slows the blood clotting process. People with this condition often experience prolonged bleeding following an injury, surgery, or having a tooth pulled. In severe cases of prothrombin deficiency, heavy bleeding occurs after minor trauma or even in the absence of injury (spontaneous bleeding). Women with prothrombin deficiency can have prolonged and sometimes abnormally heavy menstrual bleeding. Serious complications can result from bleeding into the joints, muscles, brain, or other internal organs. Milder forms of prothrombin deficiency do not involve spontaneous bleeding, and the condition may only become apparent following surgery or a serious injury.

How common is prothrombin deficiency?

Prothrombin deficiency is very rare; it is estimated to affect 1 in 2 million people in the general population.

What genes are related to prothrombin deficiency?

Mutations in the F2 gene cause prothrombin deficiency. The F2 gene provides instructions for making the prothrombin protein (also called coagulation factor II), which plays a critical role in the formation of blood clots in response to injury. Prothrombin is the precursor to thrombin, a protein that initiates a series of chemical reactions to form a blood clot. After an injury, clots protect the body by sealing off damaged blood vessels and preventing further blood loss.

F2 gene mutations reduce the production of prothrombin in cells, which prevents clots from forming properly in response to injury. Problems with blood clotting can lead to excessive bleeding. Some mutations drastically reduce the activity of prothrombin and can lead to severe bleeding episodes. Other F2 gene mutations allow for a moderate amount of prothrombin activity, typically resulting in mild bleeding episodes.

Related Gene(s)

Changes in this gene are associated with prothrombin deficiency.

  • F2

How do people inherit prothrombin deficiency?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of prothrombin deficiency?

These resources address the diagnosis or management of prothrombin deficiency and may include treatment providers.

  • Genetic Testing Registry: Prothrombin deficiency, congenital (
  • MedlinePlus Encyclopedia: Factor II deficiency (

You might also find information on the diagnosis or management of prothrombin deficiency in Educational resources and Patient support.

General information about the diagnosis ( and management ( of genetic conditions is available in the Handbook. Read more about genetic testing (, particularly the difference between clinical tests and research tests (

To locate a healthcare provider, see How can I find a genetics professional in my area? ( in the Handbook.

Where can I find additional information about prothrombin deficiency?

You may find the following resources about prothrombin deficiency helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for prothrombin deficiency?

  • dysprothrombinemia
  • factor II deficiency
  • hypoprothrombinemia

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines ( and How are genetic conditions and genes named? ( in the Handbook.

What if I still have specific questions about prothrombin deficiency?

Ask the Genetic and Rare Diseases Information Center (

What glossary definitions help with understanding prothrombin deficiency?

autosomal ; autosomal recessive ; blood clotting ; cell ; clotting ; coagulation ; deficiency ; gene ; inherited ; injury ; population ; precursor ; protein ; recessive ; spontaneous ; surgery ; thrombin ; trauma

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Akhavan S, Mannucci PM, Lak M, Mancuso G, Mazzucconi MG, Rocino A, Jenkins PV, Perkins SJ. Identification and three-dimensional structural analysis of nine novel mutations in patients with prothrombin deficiency. Thromb Haemost. 2000 Dec;84(6):989-97. (
  • Jayandharan G, Viswabandya A, Baidya S, Nair SC, Shaji RV, Chandy M, Srivastava A. Molecular genetics of hereditary prothrombin deficiency in Indian patients: identification of a novel Ala362 --> Thr (Prothrombin Vellore 1) mutation. J Thromb Haemost. 2005 Jul;3(7):1446-53. (
  • Lefkowitz JB, Weller A, Nuss R, Santiago-Borrero PJ, Brown DL, Ortiz IR. A common mutation, Arg457-->Gln, links prothrombin deficiencies in the Puerto Rican population. J Thromb Haemost. 2003 Nov;1(11):2381-8. (
  • Wong AY, Hewitt J, Clarke BJ, Hudson DM, Krisinger MJ, Dower NA, MacGillivray RT. Severe prothrombin deficiency caused by prothrombin-Edmonton (R-4Q) combined with a previously undetected deletion. J Thromb Haemost. 2006 Dec;4(12):2623-8. Epub 2006 Sep 26. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: November 2013
Published: February 8, 2016