Alagille syndrome is a rare, inherited disorder. It can affect the liver, heart, eyes, bones, kidneys and nervous system. This disorder is present at birth, although it may not become apparent until later in life.
Often, patients with Alagille syndrome have a distinctive facial appearance.
Patients may have fewer than normal bile ducts in the liver.
A small number of patients go on to develop severe liver disease and require liver transplantation.
Causes of Alagille syndrome
The disease usually is inherited from one parent. A single copy of the diseased gene (received from either the mother or father) dominates the other normal gene and results in this disease.
There is more than half of a chance that a parent with Alagille syndrome
will transmit this disorder to his or her child. Family members with Alagille syndrome may be affected very differently by the disorder.
Bile, composed of bilirubin, bile salts, cholesterol and metals such as copper, is produced in the liver and travels through small bile ducts in the liver into one large bile duct. It eventually flows into the intestines. Bile acids are necessary to absorb fat and certain vitamins. When the bile flow is decreased, each of its components builds up in the body, and the body is not able to properly absorb fat and vitamins. This causes a wide range of symptoms.
Symptoms of Alagille syndrome range from mild to severe. Symptoms within the first three months of life often include:
- Jaundice (yellowing of skin), usually present at birth
- Severe itching (caused by the build-up of bile salt in the body)
- Pale, loose or clay-coloured stools (this happens because there is little or no bile reaching the intestine to colour the bowel movements)
- Poor weight gain (due to a lack of bile needed to digest and absorb fat)
- Poor growth (even with excellent nutrition, some children with Alagille syndrome are small for age)
- Deficiency of vitamins A, D, E and K, which depend on bile acids for absorption
Other symptoms that may develop later include:
- Jaundice that will not go away
- Continued growth and development problems in early childhood
- Enlarged liver
- Hard, whitish nodules that develop in the skin due to cholesterol and fatty deposits
- Urine appears very dark yellow or brown
- Unrelenting itching
There is no cure for Alagille syndrome. Management of the disorder is aimed at preventing complications, increasing the flow of bile from the liver, maintaining normal growth and development and reducing blood cholesterol levels.
- Medications: Medicine may be used to increase bile flow and to relieve severe itching caused by build-up of bile in the blood and skin. These same medicines may be used to treat high cholesterol levels that cause the hard, whitish nodules that develop in the skin of patients with Alagille syndrome.
- Vitamin supplements: Reduced bile flow can lead to difficulty absorbing fat and vitamins from a child's diet. Fat-soluble vitamin supplements (A, D, E and K) may be used.
- High-calorie diet: Patients with Alagille syndrome often have difficulty absorbing the calories they eat. To prevent malnutrition and growth failure, a high-calorie diet with a lot of protein may be recommended. A feeding tube that delivers large quantities of nutrients overnight may be used.
- Liver transplantation: A small percentage of patients will develop cirrhosis (severe damage to the liver). Liver transplantation is the only option for these patients.
Outlook for patients depend on the severity of the bile flow obstruction and scarring of the liver, and the severity of other problems that may develop - such as heart, kidney, or nervous system problems.
Children with Alagille syndrome generally have a better outcome than children with other liver disorders at the same age. Many adults with Alagille syndrome lead normal lives.