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Activated protein C resistance and the factor V Leiden mutation in children with thrombosis
M T Sifontes1, R Nuss, S P Hunger
1The University of Colorado Health Sciences Center and the Department of Pediatrics at The Children's Hospital, Denver, USA.
Insights
Activated protein C resistance and factor V Leiden mutation are prevalent in children with thrombosis. Genetic testing for factor V Leiden is recommended for pediatric patients with non-CNS venous thrombosis, especially those with a family history.
Area of Science:
- Hematology
- Pediatric Thrombosis
- Genetics
Background:
- Thrombosis in children is a significant clinical concern.
- Activated protein C resistance (APC-R) and the factor V Leiden mutation are known risk factors for venous thromboembolism.
- The prevalence of these factors in pediatric thrombosis requires further investigation.
Purpose of the Study:
- To determine the prevalence of APC-R and the factor V Leiden mutation in children diagnosed with thrombosis.
- To assess the association between factor V Leiden mutation and non-central nervous system (non-CNS) venous thromboses in pediatric patients.
- To evaluate the clinical utility of screening for factor V Leiden in this population.
Main Methods:
- Plasma samples from children with thrombosis were analyzed for APC-R.
- DNA analysis was performed to detect the factor V Leiden mutation (G1691A).
- Clinical data, including thrombotic events and family history, were reviewed.
Main Results:
- Activated protein C resistance was identified in 5 out of 34 children (15%).
- All children with APC-R were heterozygous for the factor V Leiden mutation.
- Children with the factor V Leiden mutation experienced non-CNS venous thromboses, accounting for 21% of such events in the study group; all had a family history of thrombosis.
Conclusions:
- The factor V Leiden mutation is a significant genetic risk factor for non-CNS venous thrombosis in children.
- Pediatric patients presenting with non-CNS venous thrombosis should be evaluated for the factor V Leiden mutation.
- A family history of thrombosis increases the likelihood of identifying affected children.
Abstract:
To determine the prevalence of activated protein C resistance and the factor V Leiden mutation (position 1691, arginine 506 to glutamine substitution) in children with thrombosis, plasma samples from children with thrombosis were tested for activated protein C resistance. DNA was analyzed for the factor V Leiden mutation. Five of 34 children (15%) had activated protein C resistance; each was heterozygous for the factor V Leiden mutation. All 5 children heterozygous for the factor V Leiden mutation suffered non-CNS venous thromboses comprising 21% of the group of children (5/24) with non-CNS venous thrombotic events. Each of these 5 children had a family history of thrombosis. In conclusion, children with non-CNS venous thrombosis should be evaluated for the factor V Leiden mutation. Children most likely affected are those with a family history of thrombosis.