Significantly increased prevalence of factor V Leiden in patients with dural arteriovenous fistulas.

Resistance to activated protein C (APCR) is the most common genetic risk factor for venous thrombosis and is generally caused by a mutation in the factor V (FV) gene leading to FV Leiden. The recent finding of FV Leiden in three of seven patients with dural arteriovenous fistulas (DAVFs) prompted us to evaluate systematically the role of APCR due to FV Leiden in the pathogenesis of DAVFs in 22 patients and age- and sex-matched controls. We found a significantly higher frequency of APCR and FV Leiden in the patient group than among controls (5/22 vs. 0/22, P=0.048, Fisher's exact test). We conclude that APCR due to FV Leiden is of pathogenetic significance in a subgroup of DAVFs.