Factor V Leiden mutation is not increased in patients with inflammatory bowel disease.

Individuals with inflammatory bowel disease (IBD) are known to have an increased incidence of thromboembolic disease. Activated protein C resistance (APCR) has been identified as one of several inherited disorders of coagulation that predispose individuals to thromboembolic problems. This resistance results from a single point mutation in the factor V gene, called factor V Leiden. It has been suggested that many patients with IBD have APCR, as tested by a clotting assay. We have evaluated a series of 49 patients with IBD, none of whom had a history of thromboembolic disease. We assayed for the factor V Leiden mutation by polymerase chain reaction and found only one heterozygote. Seventeen of the 49 patients were negative for APCR by the clotting assay. Factor V Leiden mutation is not more common in patients with IBD than in the general population. We were unable to confirm a prior report indicating that patients with IBD have a higher prevalence of resistance to activated protein C.