Factor V Leiden Mutation in Cerebral Venous Thrombosis

BACKGROUND AND PURPOSE: Resistance to activated protein C is a common inherited risk factor for venous thrombosis, which is due to a mutation in coagulation factor V (factor V Leiden mutation). It is present in approximately 20% of unselected consecutive patients with deep vein thrombosis. The rate of resistance to activated protein C in patients with cerebral venous thrombosis (CVT) is unknown. METHODS: We investigated the association of factor V mutation with CVT using a case-control study. Nineteen unselected patients with CVT and 57 healthy control subjects were tested for the point mutation. RESULTS: The mutation was found in a heterozygous form in 4 of the 19 patients with CVT (21%) and in only 1 of the 57 control subjects (2%) (P = .02, Fisher's exact test). The prevalence of the coagulation defect found in our patients with CVT was consistent with that observed in previous studies in patients with deep vein thrombosis. In 3 of the 4 patients positive for the mutation, CVT developed in the presence of an acquired prothrombotic state, including oral contraceptive use in 2 patients and puerperium in the third. CONCLUSIONS: Factor V Leiden mutation is a risk factor for CVT and may be the most common inherited coagulation defect associated with this condition.