Inflammatory bowel disease (IBD) are chronic inflammatory diseases including Crohn’s disease (CD) and ulcerative colitis (UC). More than 200 genomic regions have been identified and validated (association values (5×10-8) to be associated with CD, UC or IBD. These regions may contain multiple genes and the current challenge lies in identifying the causal gene in each of these. To address this problem, we performed a functional genomic screen of 145 genes from validated IBD loci, in a relevant intestinal epithelial cell model (HT-29).