Factor V Leiden

Exam Cram

• Factor V Leiden- most common haemophilia (bleeding disorder)

• Mutation in factor V, produces protein C resistance

• Factor V allows factor Xa to activate prothrombin, producing thrombin, which produces fibrin (clot)

• Factor V mutation causes excessive clot growth (fibrin)

• Common trait (5%), not always tested for as part of a haemophilia screen, as often incidental

Med Reg Notes

Should Factor V Leiden be included in thrombophilia? 

Factor V Leiden is the commonest cause of thrombophilia. Although its autosomal dominant it has a variable penetrance. Therefore a positive result is difficult to interpret as firstly, it may not be responsible for the clot and secondly, even if it was responsible it won't change the type of long term anti-coagulant advised. For this reason some haematologists don't include it in their thrombophilia screening panel [paragraph cc'd into PE page]. 

References

1. Wilcox WR, Oliveira JP, Hopkin RJ, Ortiz A, Banikazemi M, Feldt-Rasmussen U, Sims K, Waldek S, Pastores GM, Lee P, Eng CM, Marodi L, Stanford KE, Breunig F, Wanner C, Warnock DG, Lemay RM, Germain DP: Females with Fabry disease frequently have major organ involvement: lessons from the Fabry Registry. Mol Genet Metab 2008, 93:112-128.

2. National Fabry Disease Foundation (no date) Fabry Disease. Available at: https://www.fabrydisease.org/about-fabry-disease/fabry-disease-inheritance (Accessed: 01 October 2024).

Page written in 2024. 

Produced off FOAM basis: free, open access, medical education. This is not clinical advice, education for multiple choice questions only! 

Produced to the best of the author's ability. Any issues please contact contact: MunroMedics@gmail.com