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Updated: May 15, 2025

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
A rare case of factor X deficiency induced by valproic acid
Pierre-Antonin Rigon1, Vincent Ernest2
1Aix-Marseille Université, Assistance Publique Hôpitaux de Marseille, Hôpital Conception, Centre de Néphrologie et Transplantation Rénale, Marseille, France.
Background:
Factor X (FX) deficiency (FXD) significantly disrupts coagulation, potentially leading to severe bleeding. While inherited FXD is rare, with a prevalence of 1 in 500,000, acquired FXD is also uncommon and frequently linked to conditions such as light-chain amyloidosis. In rare cases, certain medications can cause FXD.
Key Clinical Question:
Here, we present a rare case of acquired FXD induced by valproic acid (VPA). This deficiency is associated with the presence of anti-FX antibodies.
Clinical Approach:
A 65-year-old man undergoing treatment for various conditions, including chronic kidney disease and type 2 diabetes, developed severe FXD (activity <2 U/L) following VPA administration for epilepsy. During FXD, the patient experienced significant bleeding episodes, necessitating FX replacement with prothrombin complex concentrate. Upon discontinuation of VPA, FX activity improved in 9 days, possibly suggesting a role of the drug in FXD. Interestingly, antibodies directed against FX have been identified.
Conclusion:
This case emphasizes the necessity for clinicians to be vigilant of hemostasis disorders associated with VPA, even though such occurrences are rare.
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