Protein S deficiency

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Protein S deficiency
Protein PROS1 PDB 1z6c.png
Protein S
Classification and external resources
Specialty hematology
ICD-10 D68.5
ICD-9-CM 289.81
OMIM 176880
DiseasesDB 10814
eMedicine med/1924
Patient UK Protein S deficiency
MeSH D018455

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. [2]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. 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]


There are three types of hereditary protein S deficiency:[3][4]

  • Type I - decreased protein S activity: decreased total protein S levels,as well as decreased free protein S levels
  • Type II- decreased in regards to the cofactor activity of the protein
  • Type III -decreased protein S activity: decreased free protein S levels (normal total protein S levels)


Among the possible presentation of protein S deficiency are:[5][3][1]


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[4][6] Protein S deficiency can also be acquired due to vitamin K deficiency, treatment with warfarin, liver disease, and acute thrombosis (antiphospholipid antibodies may also be a cause as well)[1]


In regards to the mechanism of protein S deficiency we should start by indicating that,Protein S is principally made in liver cells. 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.[7][3]

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. [4]


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][8][9]

Differential diagnosis[edit]

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)[3]



In terms of treatment for protein S deficiency the following are consistent with the management (and administration of) individuals with this condition ( it should be noted that the prognosis for inherited homozygotes is usually in line with a higher incidence of thrombosis for the affected individual[1]):[7][3]


  1. ^ a b c d e "Protein S Deficiency. Learn about Protein S Deficiency | Patient". Patient. Retrieved 2016-10-16. 
  2. ^ "Protein S: Reference Range, Collection and Panels, Interpretation". 2016-06-01. 
  3. ^ a b c d e "Protein S Deficiency: Background, Pathophysiology, Epidemiology". 2016-05-02. 
  4. ^ a b c Reference, Genetics Home. "PROS1 gene". Genetics Home Reference. Retrieved 16 October 2016. 
  5. ^ "Congenital protein C or S deficiency: MedlinePlus Medical Encyclopedia". Retrieved 16 October 2016. 
  6. ^ Reference, Genetics Home. "protein S deficiency". Genetics Home Reference. Retrieved 16 October 2016. 
  7. ^ 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. Retrieved 16 October 2016. 
  8. ^ "Protein S blood test: MedlinePlus Medical Encyclopedia". Retrieved 16 October 2016. 
  9. ^ "Protein S deficiency - Conditions - GTR - NCBI". Retrieved 16 October 2016. 

Further reading[edit]