Protein S deficiency

Protein S deficiency
ICD-9	289.81
OMIM	176880
DiseasesDB	10814
MedlinePlus	000559
MeSH	D018455

WikiDoc Resources for Protein S deficiency
Articles
Most recent articles on Protein S deficiency Most cited articles on Protein S deficiency Review articles on Protein S deficiency Articles on Protein S deficiency in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Protein S deficiency Images of Protein S deficiency Photos of Protein S deficiency Podcasts & MP3s on Protein S deficiency Videos on Protein S deficiency
Evidence Based Medicine
Cochrane Collaboration on Protein S deficiency Bandolier on Protein S deficiency TRIP on Protein S deficiency
Clinical Trials
Ongoing Trials on Protein S deficiency at Clinical Trials.gov Trial results on Protein S deficiency Clinical Trials on Protein S deficiency at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Protein S deficiency NICE Guidance on Protein S deficiency NHS PRODIGY Guidance FDA on Protein S deficiency CDC on Protein S deficiency
Books
Books on Protein S deficiency
News
Protein S deficiency in the news Be alerted to news on Protein S deficiency News trends on Protein S deficiency
Commentary
Blogs on Protein S deficiency
Definitions
Definitions of Protein S deficiency
Patient Resources / Community
Patient resources on Protein S deficiency Discussion groups on Protein S deficiency Patient Handouts on Protein S deficiency Directions to Hospitals Treating Protein S deficiency Risk calculators and risk factors for Protein S deficiency
Healthcare Provider Resources
Symptoms of Protein S deficiency Causes & Risk Factors for Protein S deficiency Diagnostic studies for Protein S deficiency Treatment of Protein S deficiency
Continuing Medical Education (CME)
CME Programs on Protein S deficiency
International
Protein S deficiency en Espanol Protein S deficiency en Francais
Business
Protein S deficiency in the Marketplace Patents on Protein S deficiency
Experimental / Informatics
List of terms related to Protein S deficiency

For patient information click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

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 activated protein C in the proteolytic degradation of factor Va and factor VIIIa. Decreased (antigen) levels or impaired function (activity) 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% is bound to complement component C4b β-chain while the remaining 40% is free. Only free protein S has activated protein C cofactor activity.

Classification

There are three types of hereditary protein S deficiency:

• Type I - decreased protein S activity: decreased total protein S (=both bound and free protein S) levels AND decreased free protein S levels (quantitative defect)
• Type II - decreased protein S activity: normal free protein S levels AND normal total protein S levels (qualitative defect)
• Type III - decreased protein S activity: decreased free protein S levels AND normal total protein S levels (quantitative defect)

Pathophysiology

Protein S deficiency can also be acquired due to vitamin K deficiency or treatment with warfarin, systemic sex hormone therapy and pregnancy, liver disease, and certain chronic infections (for example HIV). Vitamin K deficiency or treatment with warfarin generally also impairs the coagulation system itself (factors II, VII, IX and X), and therefore predisposes to bleeding rather than thrombosis. 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).

Genetics

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.

Cost-Effectiveness of Therapy

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.