Inflammatory bowel disease inflammatory changes. Crohn's can affect any part of the gastrointestinal tract, from mouth to anus ("skip lesions"), although a majority of the cases start in the terminal ileum. Ulcerative colitis, in contrast, is restricted to the colon and the rectum. Microscopically, ulcerative colitis is restricted to the mucosa (epithelial lining of the gut), while Crohn's disease affects the full thickness of the bowel wall ("transmural lesions"). Lastly, Crohn's disease and ulcerative colitis present with extra-intestinal manifestations (such as liver problems, arthritis, skin manifestations and eye problems) in different proportions. In 10–15% of cases, a definitive diagnosis neither of Crohn's disease
Caroli disease an autosomal recessive trait. Females are more prone to Caroli disease than males. Family history may include kidney and liver disease due to the link between Caroli disease and ARPKD. "PKHD1", the gene linked to ARPKD, has been found mutated in patients with Caroli syndrome. "PKHD1" is expressed primarily in the kidneys with lower levels in the liver, pancreas, and lungs, a pattern consistent with phenotype of the disease, which primarily affects the liver and kidneys. The genetic basis for the difference between Caroli disease and Caroli syndrome has not been defined. Modern imaging techniques allow the diagnosis to be