It has long been known that patients with inflammatory bowel disease (IBD) are at higher risk of systemic throm-boembolism than is the general population. In fact, patients with both ulcerative colitis (UC) and Crohn’s disease (CD) have a 3- to 4-fold higher number of throm-boembolic events including pulmonary embolism and a 6-fold higher incidence found at autopsy.1 It has been hypothesized that prothrombotic genetic variants may be more prevalent in IBD patients than in the general population. Bernstein et al identified 492 IBD patients from the Manitoba IBD Research Registry and 412 controls from Manitoba Health’s administrative data-base. Subjects filled out questionnaires and their records were reviewed to determine their demographics, diagnosis, environmental factors, family history, smoking history, IBD phenotype, and extent and location of disease. All participants donated blood for genetic analysis, and most were contacted 2 years after venipuncture to update their history of throm-boembolic events. Subjects’ blood was analyzed for the 4 most common genetic mutations associated with the risk of thrombosis.