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Familial cerebrovascular accidents due to concomitant hyperhomocysteinemia and protein C deficiency type 1
D G Franken1, A Vreugdenhil, G H Boers
1Department of Medicine, University Hospital Nijmegen, The Netherlands.
Insights
Hyperhomocysteinemia and protein C deficiency increase blood clot risk. Their combined presence in a family led to cerebrovascular disease, suggesting a synergistic effect on thrombosis.
Area of Science:
- Vascular Medicine
- Genetics
- Thrombosis Research
Background:
- Hyperhomocysteinemia and protein C deficiency are known risk factors for thromboembolism.
- Hyperhomocysteinemia may impair protein C activity and thrombomodulin function.
- Understanding these interactions is crucial for managing thrombotic risks.
Observation:
- A family presented with independent inheritance of hyperhomocysteinemia and protein C deficiency.
- A 16-year-old girl with both conditions developed a sinus sagittalis thrombosis.
- Her father with both conditions experienced a transient ischemic attack.
- A sister with only protein C deficiency had no vascular history.
Findings:
- Clinical cerebrovascular disease manifested only in family members with the combined genetic risk factors.
- This suggests a synergistic interaction between hyperhomocysteinemia and protein C deficiency.
- Protein C deficiency alone did not appear to confer significant vascular risk in this cohort.
Implications:
- The combined presence of hyperhomocysteinemia and protein C deficiency significantly elevates the risk of cerebrovascular events.
- Genetic screening for both conditions may be warranted in patients with unexplained thrombosis.
- Further research into the synergistic mechanisms of these thrombophilic factors is needed.
Background And Purpose:
Hyperhomocysteinemia and protein C deficiency are risk factors for thromboembolism. Hyperhomocysteinemia has been reported to inhibit the expression of thrombomodulin and to inactivate both thrombomodulin and protein C irreversibly, leading to decreased protein C activity.
Case Descriptions:
In a 16-year-old girl, who developed a sinus sagittalis thrombosis, and in her father, who experienced a transient ischemic attack, both hyperhomocysteinemia and protein C deficiency type 1 were present. Protein C deficiency alone was found in one of the two sisters, who was without any clinical vascular history.
Conclusions:
In this family with independently inherited hyperhomocysteinemia and protein C deficiency, clinical cerebrovascular disease occurred only in those members with a combination of both risk factors, suggesting a synergistic interaction between these thrombogenic risk factors.