Ulcerative Colitis



Ulcerative colitis (UC) is a chronic, relapsing, inflammatory disease of the colon, which extends continuously from the rectum proximally to a varying extent. UC is categorized as an inflammatory bowel disease (IBD), along with Crohn disease (CD). Unlike CD, UC does not affect the small bowel.


  • The incidence of pediatric-onset UC is between 1 and 4 per 100,000 children per year in most North American and European regions.
  • Roughly 15–20% of patients with UC develop the disease before the age of 18 years.
  • Incidence peaks between 15 and 30 years of age.


The precise cause of UC, as with IBD in general, is unknown but is thought to involve both genetic predisposition and environmental triggers.

Risk Factors


  • Family history of IBD in ~15–20% of patients with UC
  • Higher concordance in monozygotic than in dizygotic twins
  • Genome-wide association studies (GWAS) have identified multiple loci associated with UC. Mutations in genes involving intestinal barrier functions are seen in UC more often than healthy controls.

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