Protein S deficiency


Protein S deficiency is a disorder associated with increased risk of venous thrombosis. 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. Decreased 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

Signs and symptoms

Among the possible presentation of protein S deficiency are:

Cause

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 Protein S deficiency can also be acquired due to vitamin K deficiency, treatment with warfarin, liver disease, and acute thrombosis

Pathophysiology

In regards to the mechanism of protein S deficiency, Protein S is made in liver cells and the Endothelium. 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.
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.

Diagnosis

The diagnosis for deficiency of protein S can be done via reviewing family history of condition and genetic testing, as well as the following:
Among the possibilities for differential diagnosis of protein S deficiency are- Antiphospholipid syndrome, disseminated intravascular coagulation and antithrombin deficiency

Types

There are three types of hereditary protein S deficiency:
In terms of treatment for protein S deficiency the following are consistent with the management individuals with this condition :