The Genetics of inflammatory bowel disease: What have we learned and how can we use it in our clinical practice?

Inflammatory bowel disease (IBD), an immune-mediated disease, includes Crohn's disease (CD) and ulcerative colitis (UC). It is believed that IBD occurs as a combination of environmental exposures and alterations in the intestinal microbiome that, in genetically susceptible individuals, leads to dysregulated aberrant immune activation. Genome-wide association studies have become commonplace in the last decade and have in turn elucidated many new IBD risk loci facilitating our understanding of relevant biological pathways. To date, IBD has the largest number of susceptibility variants identified among various autoimmune diseases. Despite these advances, it remains unclear what functional role these genetic variants play in disease phenotype and response to therapy; new knowledge of these biological pathways is already helping to develop novel targets for future treatment. Overall, the outlook for better treatment and prevention remain top priorities for the research community seeking to incorporate the latest genetic findings into the IBD puzzle.