Protein S deficiency
Protein S structure
SpecialtyHematology Edit this on Wikidata
SymptomsPurpura fulminans[1]
CausesVitamin K deficiency[1]
Diagnostic methodCoagulation test[1]
TreatmentHeparin, Warfarin[2]

Protein S deficiency is a disorder associated with increased risk of venous thrombosis.[1] Protein S, a vitamin K-dependent physiological anticoagulant, acts as a nonenzymatic cofactor to activate protein C in the degradation of factor Va and factor VIIIa.[3]

Decreased (antigen) levels or impaired function of protein S leads to decreased degradation of factor Va and factor VIIIa and an increased propensity to venous thrombosis. Some risk factors for deep vein thrombosis or pulmonary embolism in patients with protein S deficiency include pregnancy, older age, hormonal therapy, consumption of birth control pills, recent surgery, trauma, and physical inactivity.[4] Protein S circulates in human plasma in two forms: approximately 60 percent is bound to complement component C4b β-chain while the remaining 40 percent is free, only free protein S has activated protein C cofactor activity[medical citation needed]

Signs and symptoms

Among the possible presentation of protein S deficiency are:[1][2][5][4]


Human Chr 3

In terms of the cause of protein S deficiency it can be in inherited via autosomal dominance. A mutation in the PROS1 gene triggers the condition. The cytogenetic location of the gene in question is chromosome 3, specifically 3q11.1[6][7] Protein S deficiency can also be acquired due to vitamin K deficiency, treatment with warfarin, liver disease, kidney disease, chemotherapy, infection, surgery, birth control pills, pregnancy,[4] and acute thrombosis (antiphospholipid antibodies may also be a cause as well)[1]


In regards to the mechanism of protein S deficiency, Protein S is made in liver cells and the Endothelium.[8][9] Protein S is a cofactor of APC both work to degrade factor V and factor VIII. It has been suggested that Zn2+ might be necessary for Protein S binding to factor Xa.[2][10]

Mutations in this condition change amino acids, which in turn disrupts blood clotting. Functional protein S is lacking, which normally turns off clotting proteins, this increases risk of blood clots.[6]


PTT blood tests Vacutainer tube

The diagnosis for deficiency of protein S can be done via reviewing family history of condition and genetic testing, as well as the following:[1][11][12]

Differential diagnosis

Among the possibilities for differential diagnosis of protein S deficiency are- Antiphospholipid syndrome, disseminated intravascular coagulation and antithrombin deficiency (though this list is not exhaustive)[2]


There are three types of hereditary protein S deficiency:[2][6]


Dabigatran etexilate

In terms of treatment for protein S deficiency the following are consistent with the management (and administration of) individuals with this condition (the prognosis for inherited homozygotes is usually in line with a higher incidence of thrombosis for the affected individual[1]):[2][10]


  1. ^ a b c d e f g h "Protein S Deficiency. Learn about Protein S Deficiency | Patient". Patient. Retrieved 2016-10-16.
  2. ^ a b c d e f "Protein S Deficiency: Background, Pathophysiology, Epidemiology". 2016-05-02. ((cite journal)): Cite journal requires |journal= (help)
  3. ^ "Protein S: Reference Range, Collection and Panels, Interpretation". 2016-06-01. ((cite journal)): Cite journal requires |journal= (help)
  4. ^ a b c "Protein S Deficiency". Cleveland Clinic. Retrieved 7 February 2023.
  5. ^ "Congenital protein C or S deficiency: MedlinePlus Medical Encyclopedia". Retrieved 16 October 2016.
  6. ^ a b c Reference, Genetics Home. "PROS1 gene". Genetics Home Reference. Retrieved 16 October 2016.
  7. ^ Reference, Genetics Home. "protein S deficiency". Genetics Home Reference. Retrieved 16 October 2016.
  8. ^ "Endothelial Cells, Volume 1, 1988, p158, By Una S." Retrieved 24 January 2019.
  9. ^ Burstyn-Cohen, T.; Heeb, M. J.; Lemke, G. (2009). "J Clin Invest. 2009 Oct, 119(10):2942-53, Burstyn-Cohen T1, Heeb MJ, Lemke G: Lack of protein S in mice causes embryonic lethal coagulopathy and vascular dysgenesis". The Journal of Clinical Investigation. 119 (10): 2942–53. doi:10.1172/JCI39325. PMC 2752078. PMID 19729839.
  10. ^ a b Ten Kate, M. K.; Van Der Meer, J. (1 November 2008). "Protein S deficiency: a clinical perspective". Haemophilia. 14 (6): 1222–1228. doi:10.1111/j.1365-2516.2008.01775.x. ISSN 1365-2516. PMID 18479427. S2CID 26719614.
  11. ^ "Protein S blood test: MedlinePlus Medical Encyclopedia". Retrieved 16 October 2016.
  12. ^ "Protein S deficiency - Conditions - GTR - NCBI". Retrieved 16 October 2016.

Further reading