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One of the major features of Alagille syndrome is liver damage caused by abnormalities in the bile ducts. These ducts carry bile (which helps to digest fats) from the liver to the gallbladder and small intestine. In Alagille syndrome, the bile ducts may be narrow, malformed, and reduced in number. This results in a build-up of bile causing scarring that prevents the liver from working properly. This may lead to jaundice, itchy skin, and deposits of cholesterol in the skin (xanthomas).
Alagille syndrome is also associated with several heart problems, including impaired blood flow from the heart into the lungs (pulmonic stenosis). Other heart-related problems include a hole between the two lower chambers of the heart (ventricular septal defect) and a combination of heart defects called tetralogy of Fallot.
People with Alagille syndrome may also have distinctive facial features (including a broad, prominent forehead; deep-set eyes; and a small, pointed chin), problems with the blood vessels within the brain and spinal cord (central nervous system) and the kidneys, and an unusual butterfly shape of the bones of the spinal column (vertebrae).
Detailed information about the symptoms associated with Allagille syndrome can be accessed through the National Digestive Diseases Information Clearinghouse (NDDIC) and GeneReviews.
Research studies report that 75 percent of children diagnosed with Alagille syndrome live to at least 20 years of age. Because of improvements in liver and heart therapies, this survival rate is increasing. Many adults with Alagille syndrome who improve with treatment lead normal, productive lives. Deaths in people with Alagille syndrome are most often caused by liver failure, heart problems, and blood vessel abnormalities.