A gastrointestinal disorder characterized by chronic inflammation involving all layers of the intestinal wall, noncaseating granulomas affecting the intestinal wall and regional lymph nodes, and transmural fibrosis. Crohn disease most commonly involves the terminal ileum; the colon is the second most common site of involvement. The disease is Crohn disease (MONDO_0005011, a Monarch Disease Ontology entry). Also known as: Crohn's disease, Crohn's disease of colon, Crohn's disease of large bowel, granulomatous colitis, paediatric Crohn's disease, pediatric Crohn's disease, regional enteritis.