Crohn's disease is a 55% chance the other will too. The incidence of Crohn's disease is increasing in Europe and in newly industrialised countries. For example, in Brazil, there has been an annual increase of 11% in the incidence of Crohn's disease since 1990. Inflammatory bowel diseases were described by Giovanni Battista Morgagni (1682–1771) and by Scottish physician T. Kennedy Dalziel in 1913. "Ileitis terminalis" was first described by Polish surgeon Antoni Leśniowski in 1904, although it was not conclusively distinguished from intestinal tuberculosis. In Poland, it is still called Leśniowski-Crohn's disease (). Burrill Bernard Crohn, an American gastroenterologist at New York
Stephen Crohn Stephen Crohn Stephen Lyon Crohn (September 5, 1946 – August 23, 2013) also known as "The man who can't catch AIDS", was a man notable for a genetic mutation, which caused him to be immune to AIDS. He was a great-nephew of Burrill Bernard Crohn, for whom Crohn's disease is named. Crohn had the "delta 32" mutation on the CCR5 receptor, a protein on the surface of white blood cells that is involved in the immune system and serves as an access route for many forms of HIV virus to enter and infect host cells. This mutation rendered him effectively