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Congenital protein C deficiency and venous thromboembolism. A study of three Dutch families
Insights
Isolated protein C deficiency, crucial for blood clotting, significantly increases thrombosis risk. This study identified 18 patients with this deficiency, linking it to a history of venous thromboembolism.
Area of Science:
- Biochemistry
- Hematology
- Genetics
Background:
- Protein C is a vitamin K-dependent serine protease essential for regulating blood coagulation.
- Deficiency in protein C impairs the inactivation of activated factors V and VIII, reducing fibrinolytic capacity.
- These impairments lead to excessive fibrin formation, a significant risk factor for thrombosis.
Purpose of the Study:
- To identify and characterize individuals with isolated protein C deficiency.
- To investigate the association between protein C deficiency and venous thromboembolism.
- To determine the inheritance pattern of protein C deficiency.
Main Methods:
- Utilized an immunologic assay to measure protein C antigen levels.
- Identified 18 patients from three Dutch families with isolated protein C deficiency.
- Analyzed patient history for venous thromboembolism, particularly superficial thrombophlebitis.
Main Results:
- Mean protein C antigen concentration in deficient patients was significantly lower than in healthy subjects (0.48 U/mL vs. 0.98 U/mL).
- Patients on oral anticoagulants showed even lower protein C levels (0.17 U/mL).
- Fourteen out of 18 deficient patients had a history of venous thromboembolism, with 13 experiencing superficial thrombophlebitis.
Conclusions:
- Isolated protein C deficiency is a risk factor for venous thromboembolism.
- The condition appears to be inherited as an autosomal dominant trait with variable expressivity.
- Early identification and management are crucial for patients with protein C deficiency.
Abstract:
Protein C is the zymogen of a vitamin K-dependent serine protease involved in blood coagulation. In the absence of protein C the inactivation of activated factors V and VIIIC is impaired, and the fibrinolytic capacity of the circulating blood is reduced. These conditions promote excessive fibrin formation and thus constitute a risk factor for thrombosis. Using an immunologic assay for protein C, we identified 18 patients (11 male and 7 female) in three unrelated Dutch families as fulfilling the criteria for an isolated protein C deficiency. In 12 patients who were not receiving oral anticoagulant treatment the mean protein C antigen concentration was 0.48 +/- 0.09 U per milliliter (+/- S.D.), and in 6 patients who were receiving adjusted doses of oral anticoagulants and had stable anticoagulation, the mean value was 0.17 +/- 0.05 U per milliliter. (The value in healthy subjects is 0.98 +/- 0.19 U per milliliter.) Fourteen of the 18 patients had a history of venous thromboembolism, with superficial thrombophlebitis as the hallmark of this condition (in 13 patients). These data are consistent with an autosomal dominant trait with variable expressivity.