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Protein C and protein S deficiencies
1Unité INSERM 428, UFR des Sciences Pharmaceutiques et Biologiques, Paris, France.
Insights
Hereditary deficiencies in protein C (PC) and protein S (PS) increase thrombophilia risk. Genetic mutations cause varied disease severity, from severe neonatal complications to adult recurrent thrombosis, influenced by multiple genes.
Area of Science:
- Hematology
- Genetics
- Molecular Biology
Background:
- The protein C (PC) pathway, with its cofactor protein S (PS), is a critical endogenous antithrombotic system.
- Deficiencies in PC or PS are linked to an increased risk of thrombophilia (blood clotting disorders).
Purpose of the Study:
- To investigate the molecular basis and clinical implications of hereditary protein C and protein S deficiencies.
- To understand the heterogeneity of mutations and their impact on allele expression and thrombotic risk.
Main Methods:
- Analysis of mutation spectrum in hereditary PC and PS deficiencies.
- Correlation of genotype with clinical presentation and thrombotic events.
- Assessment of the influence of co-inherited genetic factors, such as Factor V Arg 506 to Gln mutation.
Main Results:
- Hereditary PC and PS deficiencies result from a wide array of mutations with diverse effects on gene expression.
- Homozygous or compound heterozygous mutations in the PC gene can lead to severe, early-onset thrombotic complications.
- Heterozygous individuals face a significant risk of recurrent adult thrombosis, with approximately 50% experiencing events by age 45.
- Co-inheritance of PC or PS defects with Factor V Arg 506 to Gln mutation occurs in 10-30% of symptomatic patients.
Conclusions:
- The clinical manifestation of hereditary PC and PS deficiencies is highly heterogeneous, influenced by the specific mutation and genetic background.
- Genetic factors, including mutations in PC and PS genes and other susceptibility genes, collectively determine thrombotic risk.
- Understanding these genetic underpinnings is crucial for managing patients with thrombophilia.
Abstract:
The protein C (PC) pathway, with its cofactor protein S (PS), is an important natural antithrombotic mechanism. Both PC and PS deficiencies have been implicated in thrombophilia. The molecular basis for hereditary PC and PS deficiencies is highly heterogeneous, with a large spectrum of mutations that have various effects on the expression of the relevant allele. A small subset of patients who are homozygous or compound heterozygous for a PC gene mutation have severe thrombotic complications at birth, whereas onset occurs later in the other cases. Patients heterozygous for a PC or PS gene abnormality may develop recurrent thrombosis during adulthood, with a probability of remaining free of thrombosis of about 50% at age 45. A PC or PS gene defect is associated with the factor V Arg 506 to Gln mutation in 10% to 30% of symptomatic patients, suggesting that clinical expression is controlled by several genes in heterozygous patients.