protein C deficiency
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Classification
- type 1
- most common form
- reduced immunological & biologic function; low functional & antigenic levels
- gene deletion, gene insertions
- type 2
- normal protein C antigen levels, but decreased activity
- point mutations
- homozygous* patients die in utero or in infancy
Etiology
- congenital deficiency
- acquired deficiency
- disseminated intravascular coagulation (DIC)
- extensive DVT
- malignancy
- adult respiratory distress syndrome
- sepsis/infection
- post-operative patients
- hepatic disorders
Epidemiology
- 2-3% of patients with venous thrombosis
Pathology
- impaired regulation of blood coagulation
- tendency to recurrent venous thrombosis
Genetics
- autosomal dominant (heterozygous protein C deficiency)[3]
- often develop thromoembolic disease before age 30
- however, many are asymptomatic
- autosomal recessive homoygous protein C deficiency)[4]
Clinical manifestations
- usually presents in late teens
- most common presentation is DVT followed by PE
- recurrent superficial thrombophlebitis
- neonatal purpura fulminans &/or widespread organ thrombosis shortly after birth in homozygous* patients
- homozygous form may vary from severe neonatal disease to late-onset thrombophilia
Laboratory
- protein C level (functional assay)[5]
- heterozygotes* have 30-60% of normal protein C
- serum protein C antigen low
Management
- heparin
- low molecular weight heparin
- warfarin (initial therapy with heparin) with INR of 2-3
- warfarin may cause skin necrosis & thrombosis in patients with protein C deficiency
More general terms
- blood protein disorder
- enzyme deficiency
- hypercoagulability
- genetic disease of the blood/bone marrow
Additional terms
- activated protein C (APC) resistance
- protein C in plasma (protein C assay)
- protein C; vitamin K-dependent protein C; anticoagulant protein C; autoprothrombin IIA; blood coagulation factor XIV; contains: vitamin K-dependent protein C light chain; vitamin K-dependent protein C heavy chain; activation peptide (PROC)
References
- ↑ Contributions from Linda Kuribayashi MD, Dept of Medicine, UCSF Fresno
- ↑ Medical Knowledge Self Assessment Program (MKSAP) 11, 16. 18. American College of Physicians, Philadelphia 1998, 2012, 2018
- ↑ 3.0 3.1 OMIM https://mirror.omim.org/entry/176860
- ↑ 4.0 4.1 OMIM https://mirror.omim.org/entry/612304
- ↑ 5.0 5.1 Khor B, Van Cott EM. Laboratory tests for protein C deficiency. Am J Hematol. 2010 Jun;85(6):440-2. PMID: https://www.ncbi.nlm.nih.gov/pubmed/20309856