Down the line from genome-wide association studies in inflammatory bowel disease: the resulting clinical benefits and the outlook for the future.

Inflammatory bowel disease (IBD), consisting of Crohn's disease and ulcerative colitis, is a chronic inflammatory disease of the gut. The etiology of IBD is complex, involving genetic as well as environmental factors. Genetic studies have identified 163 genetic risk loci for IBD, which have led to new insights into the biological mechanisms of the disease. The currently known IBD risk loci show an almost 75% overlap with genetic risk loci for other immune mediated diseases. Current studies are focused on the translation of the identified risk loci to clinical practice. The first steps towards this translation are being taken with the identification of genetic risk factors for drugs toxicity, specific disease course and response to therapy. In this review we will discuss how the IBD genetic risk loci were identified and how this knowledge can be translated towards clinical practice.