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
Paget's disease of bone percent of people with Paget's disease also have a family member with the disease. In cases where the disease is familial, it is inherited in an autosomal dominant fashion, although not all people that inherit the affected version of the genes will express the disease (incomplete penetrance). The incidence of Paget's disease varies considerably with geographic location. Paget's predominantly affects people of European descent, whereas people of African, Asian, or Indian descent are less commonly affected. Paget's disease is less common in Switzerland and Scandinavia than in the rest of Western Europe. Paget's disease is uncommon in the native populations