How many people are affected by Alagille Syndrome ?
Alagille syndrome occurs in about one of every 30,000 live births.3 The disorder affects both sexes equally and shows no geographical, racial, or ethnic preferences.
                
JAG1 and NOTCH2 gene mutations are inherited in an autosomal dominant way, which means a child can get Alagille syndrome by inheriting either of the gene mutations from only one parent. Each child of a parent with an autosomal dominant mutation has a 50 percent chance of inheriting the mutated gene.
                
The following chart shows the chance of inheriting an autosomal dominant gene mutation:
                
The gene mutations that cause Alagille syndrome may cause mild or subtle symptoms. Some people may not know they are affected, while others with the gene mutation may develop more serious characteristics of Alagille syndrome. A person with a gene mutation, whether showing serious symptoms or not, has Alagille syndrome and can pass the gene mutation to a child.
                
Read more about how genetic conditions are inherited at the NLM's Genetics Home Reference website at www.ghr.nlm.nih.gov.