Caroli disease is a condition characterized by an abnormal widening of the intrahepatic bile ducts (the ducts that carry bile from the liver) and renal cysts. People affected by this condition experience recurrent episodes of cholestasis, stone development in the bile ducts, and bacterial cholangitis. In addition to the symptoms of Caroli disease, people affected by Caroli syndrome may also experience liver fibrosis and portal hypertension (high blood pressure of the portal vein). Although the underlying cause of Caroli disease and Caroli syndrome are poorly understood, they are thought to be genetic conditions. Caroli disease generally occurs sporadically in people with no family history of the condition; however, rare reports exist of autosomal dominant inheritance in association with autosomal dominant polycystic kidney disease. Caroli syndrome is generally inherited in an autosomal recessive manner and is frequently seen in association with autosomal recessive polycystic kidney disease.