Low frequency of factor V Leiden and prothrombin G20210A mutations in patients with hepatic venous outflow tract obstruction in northern India: a case-control study.

BACKGROUND Factor V Leiden (FVL) and prothrombin gene (G20210A) mutations are known to be associated with venous thromboembolism. Several studies have shown an association of these mutations with hepatic venous outflow tract obstruction (HVOTO). We studied the prevalence of these mutations among patients with HVOTO in northern India in comparison with healthy population. METHODS Genomic DNA from patients with HVOTO and healthy controls was analyzed for the presence of FVL and prothrombin gene G20210A mutations, using PCR and restriction-fragment length polymorphism. RESULTS Fifty-nine patients with HVOTO (age 5-69 years, median 27; 39 male) and 49 unrelated healthy controls from the same geographic region were studied. Of the 59 patients, 19 had a block in the hepatic vein, 7 in inferior vena cava, and 33 had mixed block. Presentation was with acute thrombosis in 9 patients and with long-standing obstruction in 50 patients. Among 49 controls, heterozygous and homozygous FVL mutations were observed in 2 and 0 subjects, respectively, with an allele frequency of 2% (2 of 98). In comparison, among 59 patients with HVOTO, four had heterozygous and none had homozygous FVL mutation, with an allele frequency of 3.4% (p=ns versus controls). The G20210A prothrombin gene mutation was not found in any of the patients or controls. CONCLUSION FVL and prothrombin G20210A mutations appear to have no role in the pathogenesis of HVOTO in our patients with Budd-Chiari syndrome, consisting largely of those with long-standing obstruction of the inferior vena cava.