We therefore investigated the COX-2 −1195 A→G and −765G→C polymorphisms in relation to the development and clinical severity of IBD in a phenotypically well characterized and relatively large IBD cohort of Dutch origin and hypothesized that carriers of the −1195 A→G and/or −765G→C polymorphisms might be at risk for developing IBD. Here, PTGS2 is linked to inflammatory bowel disease.