MTHFR and inflammatory bowel disease: Several studies have shown that the prevalence of genetic mutations associated with an increased risk of VTE (for example, factor V Leiden polymorphism25,26, G20210A mutation in the prothrombin gene27, and homozygous C677T mutation in the MTHFR gene24,28–30) are similar in patients with and without IBD, and also when comparing patients with IBD with or without VTE23,31–40.