Protein S deficiency: Difference between revisions

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==Overview==
==[[Protein S deficiency overview|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 V]]a and [[factor VIII]]a.


==Classification==
==[[Protein S deficiency historical perspective|Historical Perspective]]==
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)


==Causes==
==[[Protein S deficiency classification|Classification]]==
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 [[hemorrhage|bleeding]] rather than thrombosis. 


==Pathophysiology==
==[[Protein S deficiency pathophysiology|Pathophysiology]]==


Decreased (antigen) levels or impaired function (activity) of [[protein S]], leads to decreased degradation of [[factor V]]a and [[factor VIII]]a 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.
==[[Protein S deficiency causes|Causes]]==


==[[Protein S deficiency differential diagnosis|Differentiating Protein S deficiency from other Diseases]]==


==[[Protein S deficiency epidemiology and demographics|Epidemiology and Demographics]]==


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).
==[[Protein S deficiency risk factors|Risk Factors]]==


===Genetics===
==[[Protein S deficiency natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
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.


==Diagnosis==
==Diagnosis==
*Laboratory tests will be done to check for proteins C and S. If you have this disorder, you will have a lack of protein C or S.


*Other tests that may be done include:
[[Protein S deficiency history and symptoms|History and Symptoms]] | [[Protein S deficiency physical examination|Physical Examination]] | [[Protein S deficiency laboratory findings|Laboratory Findings]] | [[Protein S deficiency other diagnostic studies|Other Diagnostic Studies]]
:*[[Bleeding time]]
 
:*[[Partial thromboplastin time]]
==Treatment==
:*[[Prothrombin time]]
 
:*[[Thrombin time]]
[[Protein S deficiency medical therapy|Medical Therapy]] | [[Protein S deficiency cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Protein S deficiency future or investigational therapies|Future or Investigational Therapies]]
 
==Case Studies==
[[Protein S deficiency case study one|Case #1]]
 
 
 
 
 
 
 
 


==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.


==References==
{{Reflist|2}}


{{Hematology}}
{{Hematology}}

Revision as of 16:36, 21 September 2012

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

Template:Protein S deficiency

For patient information click here

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

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Protein S deficiency from other Diseases

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | Other Diagnostic Studies

Treatment

Medical Therapy | Cost-Effectiveness of Therapy | Future or Investigational Therapies

Case Studies

Case #1






Template:Hematology

Template:WikiDoc Sources

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