What is the life expectancy of someone with Alagille Syndrome?

I don't believe there is one. And the thing is its not about how long you live its about how you live it. Tbh it all depends on the person that has alagilles syndrome and how serious it effects them. And treatments etc. This is a really interesting but critical question to answer. Cause there really isnt a answer at all.

The complications of Alagille syndrome include liver failure, portal hypertension, and growth problems. People with Alagille syndrome usually have a combination of complications, and may not have every complication listed below.

Liver failure. Over time, the decreased number of bile ducts may lead to chronic liver failure, also called end-stage liver disease. This condition progresses over months, years, or even decades. The liver can no longer perform important functions or effectively replace damaged cells. A person may need a liver transplant. A liver transplant is surgery to remove a diseased or an injured liver and replace it with a healthy whole liver or a segment of a liver from another person, called a donor.

Portal hypertension. The spleen is the organ that cleans blood and makes white blood cells. White blood cells attack bacteria and other foreign cells. Blood flow from the spleen drains directly into the liver. When a person with Alagille syndrome has advanced liver disease, the blood flow backs up into the spleen and other blood vessels. This condition is called portal hypertension. The spleen may become larger in the later stages of liver disease. A person with an enlarged spleen should avoid contact sports to protect the organ from injury. Advanced portal hypertension can lead to serious bleeding problems.

Growth problems. Alagille syndrome can lead to poor growth in infants and children, as well as delayed puberty in older children. Liver disease can cause malabsorption, which can result in growth problems. Malabsorption is the inability of the small intestine to absorb nutrients from foods, which results in protein, calorie, and vitamin deficiencies. Serious heart problems, if present in Alagille syndrome, can also affect growth.

Malabsorption. People with Alagille syndrome may have diarrhea—loose, watery stools—due to malabsorption. The condition occurs because bile is necessary for the digestion of food. Malabsorption can lead to bone fractures, eye problems, blood-clotting problems, and learning delays.
Long-term Outlook

The long-term outlook for people with Alagille syndrome depends on several factors, including the severity of liver damage and heart problems. Predicting who will experience improved bile flow and who will progress to chronic liver failure is difficult. Ten to 30 percent of people with Alagille syndrome will eventually need a liver transplant.3

Many adults with Alagille syndrome whose symptoms improve with treatment lead normal, productive lives. Deaths in people with Alagille syndrome are most often caused by chronic liver failure, heart problems, and blood vessel problems.