Caroli disease is a rare genetic disorder that affects the bile ducts, which carry bile from the liver to aid in the digestion of fats. Researchers have identified two forms of Caroli disease. The isolated, or simple, form is characterized by a widening of the bile ducts. The complex form, which is also referred to as Caroli syndrome, is similarly characterized by a widening of the bile ducts, but malformations of the smaller bile ducts, congenital hepatic fibrosis (scarring of liver tissue), high blood pressure, and kidney problems are also present. The differences in the causes for the two forms have not yet been discovered. For the purposes of this article, the isolated form of Caroli disease will be referred to simply as Caroli disease, while the more severe form will be referred to as Caroli syndrome.
The exact genetic mutation causing Caroli disease and Caroli syndrome is not known. However, some individuals with Caroli syndrome may have a mutation in the PKHD1 gene. PKHD1 is found primarily in the kidneys, with lower levels in the liver, pancreas, and lungs. The PKHD1 gene encodes for a protein called fibrocystin, which is a receptor-like protein thought to be involved in tubulogenesis and bile duct maintenance. A mutation in this gene is also thought to cause autosomal recessive polycystic kidney disease.
The simple form of Caroli disease is inherited, or passed down among family members, as an autosomal dominant trait. It may also occur in individuals with no family history of the disorder as the result of a spontaneous genetic mutation in the egg or sperm cells or in the developing embryo. The complex form, Caroli syndrome, is inherited as an autosomal recessive trait.
Caroli disease and Caroli syndrome are very rare, affecting about 1 in 1,000,000 people. Caroli syndrome is more common than Caroli disease, although it is unclear to what degree. Symptoms appear first in adults, although childhood and neonatal cases have been reported. There is no cure for Caroli syndrome or disease. Treatment involves managing symptoms. Mortality in Caroli disease is caused by complications. After cholangitis (inflammation of the bile duct) occurs, which it does in both the disease and the syndrome, a large number of patients die within 5-10 years. The average age of patients at diagnosis is 22 years. Both conditions are more common in females than in males.
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types of the disease
Caroli disease: Caroli disease, also known as isolated or simple Caroli disease, is the milder and less common of the two forms of the condition. Caroli disease is characterized by a widening of the larger bile ducts. This form of the disease is inherited, or passed down among family members, as an autosomal dominant trait.
Caroli syndrome: Caroli syndrome, or complex Caroli disease, is the more severe and common form of the condition. In addition to widening of the small bile ducts, Caroli syndrome is associated with high blood pressure, kidney problems, including polycystic kidney disease, and occasionally liver disease. This form of the disease is inherited as an autosomal recessive trait.