^

Health

A
A
A

Protein S deficiency: causes, symptoms, diagnosis, treatment

 
, medical expert
Last reviewed: 13.03.2024
 
Fact-checked
х

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

Protein S is a non-enzymatic cofactor of protein C in the inactivation of factors Va and VIIIa, has its own protein-independent C anticoagulant activity.

Protein S, as well as protein C, is dependent on vitamin K and synthesized in the liver. In the circulation it exists in 2 forms - free protein S and associated with the C4-component of complement. Normally 60-70% of protein S is associated with the C4-component of complement - the regulator of the classical pathway of the complement system. The level of binding of protein S to the C4 complement component determines the content of free protein S. Only the free form of protein S serves as a cofactor of activated protein C (APC).

Normally, the protein S level in plasma is 80-120%. In pregnancy, the level of both free and bound protein S is reduced and is 60-80% and lower in the postoperative period.

Protein S deficiency is inherited autosomal dominant. Carriers of gene mutation are more often heterozygous, carriers-homozygotes are rare. It was found that the gene for protein S is located on chromosome 3. Up to 70 mutations of the protein S gene are currently known. The hereditary deficiency of protein S can be of 2 types:

  • I type - reduction of the level of free protein S, associated with the C4-component of complement, within the limits of the norm;
  • Type II - reduction in the level of free and bound protein S. According to the researchers, the frequency of pregnancy loss is 16.5%. More often observed stillbirths than the early loss of pregnancy.

trusted-source[1], [2], [3], [4], [5], [6], [7], [8]

What tests are needed?

Treatment of the protein deficiency S

Treatment of protein deficiency S

Patients with deficiency of protein C and S are refractory to sodium heparin and antiaggregants. However, with acute thrombotic complications, the use of heparin sodium and then low-molecular heparins is justified. As a source of proteins, C and S use fresh frozen plasma in combination with heparin sodium. Out of pregnancy with thrombophilia for a long time used warfarin.

You are reporting a typo in the following text:
Simply click the "Send typo report" button to complete the report. You can also include a comment.