About Alagille Syndrome
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
Alagille syndrome is a genetic syndrome that can affect the liver and other parts of the body. The liver problems result from having fewer small bile ducts than normal in the liver. This leads to bile building-up inside the liver, which in turn causes liver scarring and damage. Signs and symptoms of Alagille syndrome are generally noticed in infancy or early childhood. Type of symptoms and severity varies greatly, even among people in the same family, so that in some cases the symptoms are severe, and in others, very mild. The liver problems may be the first symptoms of the syndrome, and may include yellow color of the skin and whites of the eyes (jaundice); itchy skin; bumps on the skin caused by deposits of cholesterol and fats (xanthomas); pale, loose bowel movements; and poor growth. Alagille syndrome can also affect other parts of the body including the heart, brain, kidneys, blood vessels, eyes, face, and skeleton. People with Alagille syndrome may have distinctive facial features too, including a broad, prominent forehead, deep-set eyes, and a small, pointed chin. Alagille syndrome is caused by changes in the JAG1 and NOTCH2 genes. Inheritance is autosomal dominant. However, in about half of cases the genetic change occurs as a new change (“de novo”) without being inherited from either parents.
Causes
What Causes This Disease?
Genetic Mutations: Alagille syndrome is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.
Can This Disease Be Passed Down From Parent to Child?
Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.
There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):
Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.
People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.