Frequent factor II G20210A mutation in idiopathic portal vein thrombosis

Background & Aims: Despite extensive investigations of portal vein thrombos is, no underlying cause is identifiable in up to 30% of patients. A recentl y described mutation of the prothrombin gene at nucleotide position 20210 i s associated with history of venous thrombosis and was assessed in this stu dy. Methods: We compared the frequency of factor II G20210A and factor V G1 691A (factor V Leiden) mutations in 10 patients with idiopathic portal vein thrombosis, 10 patients with nonidiopathic portal vein thrombosis, 60 pati ents with deep vein thrombosis of the legs, and 42 control subjects. Result s: The frequency of factor II G20210A mutation was increased in patients wi th idiopathic portal vein thrombosis (40.0%; confidence interval, 3.1%-76.9 %) compared with controls (4.8%; confidence interval, 0%-11.5%) or patients with nonidiopathic portal vein thrombosis or deep vein thrombosis (P = 0.0 001). In contrast, the frequency of the factor V G1691A mutation was simila r in subjects with portal vein thrombosis and in controls but was increased in patients with deep vein thrombosis (P = 0.0001). Conclusions: The facto r II G20210A mutation is frequent in patients with idiopathic portal vein t hrombosis and should therefore be assessed under this circumstance.