Protein S deficiency is a disorder associated with increased risk of thrombosis. Decreased levels or impaired function of protein S, a vitamin K-dependent physiological anticoagulant, leads to decreased degradation of factor Va and factor VIIIa and an increased propensity to venous thrombosis. Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the liver and it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa. ... Vitamin K denotes a group of 2-methilo-naphthoquinone derivatives. ... Factor V is a protein of the coagulation system, rarely referred to as proaccelerin or labile factor. ... Factor VIII (FVIII) is an essential clotting factor. ...

Types

There are three types of hereditary protein S deficiency:

• Type I - decreased protein S activity: low levels of free protein S, normal levels of bound protein S
• Type IIa - decreased protein S activity: low levels of free protein S, low levels of bound protein S
• Type IIb - decreased protein S activity: normal levels of free protein S, normal levels of bound protein S

Decreased activity is present in an acquired form in vitamin K deficiency or treatment with warfarin. This generally also impairs the coagulation system itself (factors II, VII, IX and X), and therefore predisposes to bleeding rather than thrombosis. Protein S levels are also lower in pregnancy and liver disease. Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the liver and it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa. ... Warfarin (also known under the brand names of Coumadin®, Jantoven®, Marevan®, and Waran®) is an anticoagulant medication that is administered orally or, very rarely, by injection. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A pregnant woman near the end of her term Pregnancy is the carrying of one or more embryos or fetuses by female mammals, including humans, inside their bodies. ...

Protein S deficiency is the underlying cause of a small proportion of cases of disseminated intravascular coagulation (DIC), deep venous thrombosis (DVT) and pulmonary embolism (PE). Disseminated intravascular coagulation (DIC) is a pathological process in the body where the blood starts to coagulate throughout the whole body. ... It has been suggested that Deep Vein Thrombosis be merged into this article or section. ...

Hereditary PSD is an autosomal dominant condition, resulting in a 50 percent chance of passing the disease to offspring. Less than half of those diagnosed with PSD will experience thrombosis, and those who do usually are affected only from the age of the late teens onwards. A positive blood test can lead to the loss of health insurance benefits and/or employment, and the social downsides need to be balanced against the actual medical benefit of accurate diagnosis. Screening of young children is usually deferred because early testing is often inaccurate, and it is better to wait until they are old enough to decide for themselves whether they want to be tested. An autosomal dominant gene is one that occurs on an autosomal (non-sex determining) chromosome. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... Blood tests are laboratory tests done on blood to gain an appreciation of disease states and the function of organs. ... This article or section does not cite its references or sources. ... Employment is a contract between two parties, one being the employer and the other being the employee. ...

External links

• Mendelian Inheritance in Man (OMIM) 176880
• Protein S Deficiency And Thrombophilia