Crohn's disease after gastroenterologist Burrill Bernard Crohn, who, in 1932, together with two other colleagues at Mount Sinai Hospital in New York, described a series of patients with inflammation of the terminal ileum of the small intestine, the area most commonly affected by the illness. Many people with Crohn's disease have symptoms for years before the diagnosis. The usual onset is between 15 and 30 years of age, but can occur at any age. Because of the 'patchy' nature of the gastrointestinal disease and the depth of tissue involvement, initial symptoms can be more subtle than those of ulcerative colitis. People with
Crohn's disease the risk of developing Crohn disease are ATG16L1, IL23R, IRGM, and SLC11A1. There is considerable overlap between susceptibility loci for IBD and mycobacterial infections. Recent genome-wide association studies have shown that Crohn's disease is genetically linked to coeliac disease. Crohn's has been linked to the gene LRRK2 with one variant potentially increasing the risk of developing the disease by 70%, while another lowers it by 25%. The gene is responsible for making a protein, which collects and eliminates waste product in cells, and is also associated with Parkinson's disease. There was a prevailing view that Crohn's disease is a primary