What is Alagille syndrome?
Alagille syndrome is a multi-system hereditary disorder. It often presents with clinical symptoms involving the liver during infancy and early childhood. Alagille syndrome is named after the French pediatric liver specialist who first recognized the clinical features of the syndrome.
Seen throughout the world in many races, Alagille syndrome is more commonly reported in boys, although girls are also affected. Alagille syndrome is the most common form of the inherited disorders which cause reduced bile flow within the liver.
Genetic research of the chromosomes of patients with Alagille syndrome has found mutations in the Jagged 1 gene.
The diagnosis of Alagille syndrome usually depends upon finding several different components of the syndrome in an individual. The classic syndrome involves five distinct findings, including: Chronic cholestasis (reduced bile flow). Symptoms usually begin in infancy with jaundice, itching, and cholesterol deposits in the skin (xanthomas). A liver biopsy shows that there are not enough bile ducts within the liver.
Congenital heart disease. Usually peripheral pulmonic stenosis, although other heart disorders such as Tetralogy of Fallot and coarctation of the aorta have been reported.
Bone defects. Usually "butterfly" or Hemi-vertebrae in the spine.
Eye findings. Usually an extra thickening of a line, known as the Schwalbe’s line, on the surface of the eye. Less common eye findings include retinal pigment changes.
Typical facial features. Often with deep set eyes, frontal bossing, bulbous tip of the nose, a down-turned mouth, and a small mandible with pointed chin.
Note: Not all patients with Alagille syndrome demonstrate all of these different findings.
Complications and Treatments
The management of Alagille syndrome is aimed primarily at preventing complications and treating symptoms. Because Alagille patients have reduced bile flow, they are at risk to develop fat soluble vitamin deficiency. Supplementation of fat soluble vitamins (A,D,E,K) and monitoring serum levels of these vitamins is warranted in these children. They can also have difficulty absorbing fat from their diet. In infancy, formulas rich in medium chain triglycerides (MCT) should be utilized to maximize fat absorption. The goal is to maximize the growth and development of these children.
Itching (pruritus) associated with reduced bile flow can be significant and difficult to treat. The use of drugs such as phenobarbital, cholestyramine and ursodeoxycholic acid (Actigall) may be helpful in individual patients. Other drugs such as Atarax and Benadryl may give temporary symptomatic relief.
Surgery may on occasion be necessary to obtain an adequate sample of liver tissue to examine the bile duct system. The Kasai portoenterostomy, used for biliary atresia, does not replace bile ducts within the liver and has no value for the patient with Alagille syndrome. Partial external biliary diversion has been occasionally used for the treatment of "unstoppable itching" and severely elevated cholesterol levels. In this surgical procedure, a connection is made between the gallbladder and the skin so bile may be drained to the outside of the body. The success of this procedure for Alagille syndrome has not been as dramatic as for other forms of inherited liver disease.
Liver transplantation has been used successfully for selected patients with Alagille syndrome.