Crohn's and other inflammatory bowel diseases are painful and debilitating, but there are no known cures for the diseases. The symptoms have to be managed by the individual with professional help. It is widely thought that IBDs develop as a result of an individual's genetic make-up, their gut microbiota, and environmental cues, though it is not fully understood how these factors promote IBDs. A new study in the Journal of Clinical Investigation identifies a specific gene expression profile and microbial community associated with Crohn's disease. Lee Denson and colleagues at Cincinnati Children's Hospital Medical Center compared the intestines of healthy patients to pediatric Crohn's disease patients. Crohn's disease patients had altered expression of 2 genes, DUOX2 and APOA1, as well as a distinct microbial community. Furthermore, APOA1 expression and microbial abundance could be used to predict clinical outcomes in Crohn's disease patients.