Related Experiment Video
Updated: Aug 17, 2026

Mouse Complete Stasis Model of Inferior Vena Cava Thrombosis
Published on: June 15, 2011
[Homocysteine and venous thromboembolism]
1Division des maladies vasculaires et de l'hypertension, Département de médecine interne, Centre hospitalier et universitaire vaudois, Lausanne.
Insights
Moderate hyperhomocysteinemia increases the risk of venous thromboembolism. Screening for high homocysteine levels is recommended for idiopathic thrombosis, with folic acid potentially beneficial for mild cases.
Area of Science:
- Biochemistry
- Genetics
- Cardiovascular Medicine
Background:
- Congenital homocysteinuria is a rare inherited disorder linked to early atherosclerosis and thrombosis.
- Moderate hyperhomocysteinemia is a prevalent cardiovascular risk factor, associated with venous thromboembolism (VTE).
- Mild hyperhomocysteinemia, especially with Factor V Leiden mutation, significantly elevates VTE risk.
Purpose of the Study:
- To review the association between hyperhomocysteinemia and thrombosis.
- To discuss the potential mechanisms of homocysteine-induced thrombosis.
- To evaluate the role of screening and folic acid treatment.
Main Methods:
- Review of case-control studies on hyperhomocysteinemia and venous thromboembolism.
- Analysis of biochemical mechanisms linking homocysteine to thrombosis.
- Evaluation of existing literature on folic acid treatment efficacy.
Main Results:
- Moderate hyperhomocysteinemia confers a 2-3 fold increased risk of VTE.
- Mild hyperhomocysteinemia with Factor V Leiden mutation increases VTE risk tenfold.
- Homocysteine may promote thrombosis by inhibiting thrombomodulin and antithrombin-III binding.
Conclusions:
- Hyperhomocysteinemia should be screened in patients with idiopathic thromboembolism.
- Folic acid reduces homocysteine levels, and a trial may be justified for mild hyperhomocysteinemia.
- Further studies are needed to confirm folic acid's efficacy in reducing VTE and atherosclerosis.
Abstract:
Congenital homocysteinuria is a rare inherited metabolic disorder with early onset atherosclerosis and arterial and venous trombosis. Moderate hyperhomocysteinemia is more frequently encountered and is recognized as an independent cardiovascular risk factor. Several case-control studies demonstrate an association between venous thromboembolism and moderate hyperhomocysteinemia. A patient with moderate hyperhomocysteinemia has a 2-3 relative risk of developing an episode of venous thromboembolism. The occurrence of mild hyperhomocysteinemia in heterozygotes for the mutation of Leiden factor V involves a 10-fold increase in the risk of venous thromboembolism. The biochemical mechanism by which homocysteine may promote thrombosis is not fully recognized. Homocysteine inhibits the expression of thrombomodulin, the thrombin cofactor responsible for protein C activation, and inhibits antithrombin-III binding. Treatment with folic acid reduces the plasma level of homocysteinemia, but no study has demonstrated its efficacy in reducing the incidence of venous thromboembolism or atherosclerosis. Hyperhomocysteinemia should be included in the screening of abnormalities of hemostasis and thrombosis in patients with idiopathic thromboembolism, and mild hyperhomocysteinemia may justify a trial of folic acid.
Related Concept Videos
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Disorders of Hemostasis
Thromboembolic Disorders
Two factors primarily cause thromboembolic conditions.
Venous Thrombosis I: Introduction
Venous Thrombosis II: Clinical Manifestations and Diagnostic Studies
Venous Thrombosis III: Interprofessional Care
Venous Thrombosis IV: Nursing Management

