Coagulation
Hereditary thrombophilia / hypercoagulopathies
Protein C deficiency
Author: Jeremy C. Parsons, M.D.
Last author update: 1 June 2012
Last staff update: 23 September 2020
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Protein C deficiency [title]
Cite this page: Parsons JC. Protein C deficiency. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/coagulationproteinCdef.html. Accessed December 23rd, 2024.
Definition / general
- Hereditary deficiencies occur in 0.14 - 0.5% of general population (the clinically significant incidence is much lower)
- > 160 mutations exist, either type I (76%, usually quantitative) or type II (dysfunctional protein, normal protein levels)
- Causes 1 - 11% of cases of venous thrombosis
- These patients are also at risk for warfarin-induced skin necrosis if treated with warfarin and no heparin until warfarin levels are therapeutic; this paradoxical clotting is due to a faster fall in natural anticoagulant proteins than procoagulant proteins in these patients
- Heterozygotes have levels 35 - 65% of normal
- First thrombotic event occurs between ages 10 - 50 years
- Only 30% have thromboembolism, increasing to 75% if coexisting factor V Leiden
- Homozygotes (1 per 500 - 750K births) with severely decreased levels present as newborns with DIC and purpura fulminans neonatorum, leading to death unless anticoagulation and replacement therapy with fresh frozen plasma is started
- Homozygous protein C deficiency can be cured with liver transplant; however, this is usually too risky so replacement is preferred treatment
- Must exclude acquired causes of protein C deficiency
Etiology
- Acquired causes of low protein C levels:
- Clot formation
- Surgery
- Liver disease
- Warfarin (should be discontinued at least 10 days prior to testing) or Vitamin K antagonist therapy
- DIC
- Vitamin K deficiency
- L-asparaginase therapy
- Acquired causes of increased protein C (may mask protein C deficiency):
- Ischemic heart disease
- Pregnancy
- Postmenopausal women
- Hormone replacement therapy
- Oral contraceptives
Clinical images
Images hosted on other servers:
Warfarin induced skin necrosis
Additional references
