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PROC gene

protein C, inactivator of coagulation factors Va and VIIIa

Normal Function

The PROC gene provides instructions for making a protein called protein C that is important for controlling blood clotting. Protein C blocks the activity of two proteins that promote the formation of blood clots, called factor Va and factor VIIIa. Protein C is also involved in controlling inflammation. Inflammation is a normal body response to infection, irritation, or other injury.

Protein C is made in the liver and then released into the bloodstream. The protein remains turned off (inactive) until it attaches to a protein called thrombin, which converts it to activated protein C (APC). APC cuts (cleaves) the factor Va protein at specific sites, which partially or completely inactivates factor Va. (The inactive form is called factor V.) APC then works with factor V to inactivate factor VIIIa.

Health Conditions Related to Genetic Changes

Protein C deficiency

At least 270 mutations in the PROC gene have been found to cause protein C deficiency. Most of these mutations change single protein building blocks (amino acids) in protein C, which disrupts its ability to control blood clotting. Protein C deficiency can be divided into type I and type II based on the mutation in the PROC gene.

Protein C deficiency type I is caused by PROC gene mutations that result in reduced levels of protein C. Affected individuals do not have enough protein C to control blood clotting, which causes the increased risk for abnormal blood clots in protein C deficiency.

Mutations that cause protein C deficiency type II result in the production of an altered protein C with reduced activity. Individuals with this form of the condition have normal levels of protein C, but the protein is not able to interact with other molecules involved in blood clotting. If protein C cannot control blood clotting, abnormal blood clots may form.

More About This Health Condition

Other Names for This Gene

  • PC
  • PROC1
  • protein C
  • protein C (inactivator of coagulation factors Va and VIIIa)

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Brouwer JL, Lijfering WM, Ten Kate MK, Kluin-Nelemans HC, Veeger NJ, van der Meer J. High long-term absolute risk of recurrent venous thromboembolism in patients with hereditary deficiencies of protein S, protein C or antithrombin. Thromb Haemost. 2009 Jan;101(1):93-9. Citation on PubMed
  • D'Ursi P, Marino F, Caprera A, Milanesi L, Faioni EM, Rovida E. ProCMD: a database and 3D web resource for protein C mutants. BMC Bioinformatics. 2007 Mar 8;8 Suppl 1(Suppl 1):S11. doi: 10.1186/1471-2105-8-S1-S11. Citation on PubMed or Free article on PubMed Central
  • Goldenberg NA, Manco-Johnson MJ. Protein C deficiency. Haemophilia. 2008 Nov;14(6):1214-21. doi: 10.1111/j.1365-2516.2008.01838.x. Citation on PubMed
  • Knoebl PN. Severe congenital protein C deficiency: the use of protein C concentrates (human) as replacement therapy for life-threatening blood-clotting complications. Biologics. 2008 Jun;2(2):285-96. doi: 10.2147/btt.s1954. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.