Alagille syndrome

What is Alagille syndrome?

Alagille syndrome is a genetic disorder that includes a certain set of symptoms.

It is caused by a chromosomal modification of the JAG1 gene on chromosome 20 or the NOTCH2 gene on chromosome 1.

This rare disease affects 1 child in 100,000 births.

How is it transmitted?

The mutation can either occur during the embryonic period and in this case, it is considered to be acquired, or it is transmitted by one of the parents.
Genetic analysis can confirm the diagnosis

What are the symptoms?

Prolonged yellow coloring of the skin (jaundice) in the newborn is often the first form of presentation of the disease.

This jaundice is associated with neonatal cholestasis (biliary retention) due to a weak biliary network.

A reduction in the number of bile ducts in the liver also leads to an accumulation of “conjugated” bilirubin in the blood.

In addition to jaundice, the child may also have itching (pruritus), which is caused by this high level of conjugated bilirubin.

Other symptoms or signs are found to varying degrees in Alagille syndrome, such as:

• Cardiac malformations (the most common being stenosis of the pulmonary artery)
• Vertebral anomalies with the appearance of "butterfly wings" in X-rays
• A characteristic face shape
• An iris anomaly called embryotoxon (fatty deposit around the iris)
• Kidney problems
• Small body size.

How is it diagnosed?

When signs suggestive of this syndrome are shown, genetic analysis can confirm the diagnosis, since mutations of the gene have been identified.

What are the treatments?

Treatment depends on the symptoms, which can vary. Some patients essentially only have heart problems.

In the case of persistent jaundice, dietary measures should be taken to avoid vitamin deficiency and to ensure proper growth.

Pruritus can be reduced by a medication called rifampicin.

Liver transplantation is indicated if the pruritis is not relieved by drug therapy or if the disease progresses to severe liver complications.