I have a child with Alagille syndrome. What are the chances that I will have another child with Alagille syndrome, as well?
That depends on whether or not you or your partner have the same genetic change as your child with Alagille syndrome. If one of you has the same genetic change, there is a 1 in 2, or 50%, chance of each of your future children having Alagille syndrome. This does not mean that 50% of your children will have Alagille syndrome, but that each child has a 50% chance of inheriting it.
If neither of you has the same genetic change, the chance of having another child with Alagille syndrome is low, but it is not impossible. It is always possible, but highly unlikely, that the random event that caused the genetic change in your child could happen again. It is also possible that you or your partner is "mosaic" for a genetic change that cause Alagille syndrome. "Mosaic" means that some of the cells in your body have a genetic change and some don't. If someone is mosaic for a genetic change, there is a chance that they can pass this change on to their children.