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protein S deficiency
Classification:
- type 1:
- low serum protein S antigen
- low protein S activity
- type 2: (rare)
- normal serum protein S antigen
- free protein S antigen normal
- low protein S activity
- type 3, in which
- normal serum protein S antigen
- free protein S antigen low
- low protein S activity
Etiology:
1) hereditary defect
2) autoantibodies to protein S may occur in association with lupus anticoagulant, especially in children after infection (varicella)
3) pregnancy is associated with type 3
- protein S activity as low as 30% 2-3 weeks before delivery
4) HIV/AIDS patients may be susceptible
Epidemiology:
- accounts for 2-10% of thrombotic events
Pathology:
- thrombophilia
- impaired regulation of blood coagulation
- tendency to recurrent venous thrombosis
Genetics:
- autosomal dominant inheritance
- associated with defects in protein S (PROS1)
Clinical manifestations:
1) homozygous individuals
a) high intrauterine mortality
b) may develop fulminant purpura fulminans during infancy
2) heterozygotes
a) present with 1st thrombotic event in mid to late teens
b) many adults are asymptomatic
Laboratory:
- serum protein S activity (functional assay)
- serum protein S antigen
- free protein S antigen
Management:
1) heparin
2) low molecular weight heparin
3) warfarin (initial therapy with heparin) with INR of 2-3
Related
protein S activity in plasma (protein S assay)
protein S; vitamin K-dependent protein S (PROS1, PROS)
General
blood protein disorder
hypercoagulability
genetic disease of the blood/bone marrow
Database Correlations
OMIM 612336
References
- Contributions from Linda Kuribayashi MD, Dept of
Medicine, UCSF Fresno
- Medical Knowledge Self Assessment Program (MKSAP) 11, 16.
American College of Physicians, Philadelphia 1998, 2012
- OMIM :accession 612336
- ten Kate MK, van der Meer J.
Protein S deficiency: a clinical perspective.
Haemophilia. 2008 Nov;14(6):1222-8.
PMID: 18479427