Update on genetics in inflammatory disease

Crohn's disease and ulcerative colitis are chronic inflammatory disorders caused by a disruptive interaction between the immune system and gut luminal factors. Although the exact aetiology of IBD remains unclear, accumulating data, including genome-wide association studies (GWAS), have advanced our understanding of the immunopathogenesis. This review highlights the role in gut homeostasis and IBD pathogenesis. It focuses on past and recent advances in our understanding of IBD, including genetics and immunobiology. Recently published GWAS have confirmed earlier findings related to the NOD2 gene and the IBD5 locus. In addition, over 30 novel loci have been identified. Several promising associations between Crohn's disease and gene variants have been identified and replicated, the two most widely replicated being variants in the IL23R and ATG16L1 genes. These findings highlight and further support the importance of the immune system and its interactions with the intestinal flora in the pathogenesis of inflammatory bowel disease.