Factor V Leiden thrombophilia is characterized by a poor anticoagulant response to activated protein C
(APC) and an increased risk for venous thromboembolism (VTE). Deep venous thrombosis (DVT) is the most
common VTE, with the legs being the most common site. Factor V Leiden thrombophilia is suspected in
individuals with a history of venous thromboembolism (VTE) manifest as deep vein thrombosis (DVT) or
pulmonary embolism, in women with a history of VTE during pregnancy or in association with oral
contraceptive use, and in individuals with a personal or family history of recurrent thrombosis. The
variant Factor V Leiden is inactivated by APC at a rate approximately ten times slower than normal factor
V and persists longer in the circulation, resulting in increased thrombin generation and a mild
hypercoagulable state, reflected by elevated levels of prothrombin fragment F1+2 and other activated
coagulation markers. The diagnosis of factor V Leiden thrombophilia is made either using a coagulation
screening test (APC resistance assay) or by DNA analysis of the F5 gene which encodes the factor V
protein, the only gene associated with factor V Leiden thrombophilia. The term "factor V Leiden" refers to
the specific G-to-A substitution at nucleotide 1691 in the gene for factor V that predicts a single
amino-acid replacement (Arg506Gln) at one of three APC cleavage sites in the factor V molecule.
Reference :
- Desjonquères, A., Ménard, A., Detemmerman, L., Ternisien, C., Fouassier, M., Gillet, B., … Le Bris,
Y. (2019). Confirmed validation of an innovative PCR-assay without DNA extraction for multiplex
diagnosis of factor V Leiden and prothrombin gene variants. Thrombosis Research, 183, 143–145. Available
from : Thrombosis Research