Alagille Syndrome

From WikiGenetics

1 Name of Condition
2 Definition
3 Description, Signs and Symptoms
4 Inheritance
5 Demographics
6 Diagnosis
7 Treatment and Management
8 Prognosis
9 Resources
10 References

[edit] Name of Condition

Alagille Syndrome (AGS), also known as Watson-Alagille Syndrome, Arteriohepatic Dysplasia, AHD

[edit] Definition

Alagille Syndrome is a genetic liver disease that is caused by malformation or absence of bile ducts. It causes liver damage and also affects the eyes, heart, face, and bones.

[edit] Description, Signs and Symptoms

Symptoms of Alagille Syndrome include:

Jaundice due to liver disease
stunted growth
eye and heart structure abnormalities
some mental retardation
butterfly vertebrae
characteristic facial features including a broad, prominent forehead, deep-set eyes, and a small chin

Due to the abnormalities in the liver, children with AGS cannot digest certain types of fats. However, they can take baby formula that contains high levels of medium-chain triglycerides (MCT) and can grow normally by drinking that along with breastfeeding. The disease usually stabilizes between the ages of 4 and 10, although sometimes complications may occur.

[edit] Inheritance

Alagille Syndrome is an autosomal dominant disorder, meaning if one parents has the condition, there is a 50% chance their child will also have it. Two genes have been identified that contribute to AGS, JAG1 and NOTCH2. Usually a mutation in only one of these genes will cause the disorder; people with AGS have either the JAG1 or the NOTCH2 mutation, but not both. Of the two, the JAG1 mutation is far more common, occuring in about 88% of patients with AGS.

Approximately 30-50% of cases of AGS are directly inherited from a parent. 50-70% of cases arise due to spontaneous mutations.

[edit] Demographics

Alagille Syndrome occurs in approximately 1 in 70,000 children.

[edit] Diagnosis

Doctors would diagnose Alagille Syndrome based on abnormalities of the bile ducts, in conjunction with three of the five following problems:

cholestasis, or blockage of bile flow
cardiac defect
skeletal abnormalities
facial features
ophthalmologic (eye) abnormalities

Alagille Syndrome is usually difficult to diagnose because there are many types of disorders that cause similar symptoms, and AGS is a rare disorder.

[edit] Treatment and Management

In some cases, surgery may be necessary to determine the status of the liver and bile ducts. Reconstructive surgery of the bile ducts is not recommended because the liver can function without them, although problems with fat digestion and absorption may require that the child takes vitamin supplements. In more rare cases, liver cirrhosis may occur, and progress to a stage where a liver transplant could be necessary.

Otherwise, treatment typically only requires management of symptoms.

[edit] Prognosis

In many children the disease stabilizes in early childhood, however some complications may occur involving liver cirrhosis that could result in early death if a liver transplant is not received.