Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Alagille syndrome ?
    ### Response:
    In more than 90 percent of cases, mutations in the JAG1 gene cause Alagille syndrome. Another 7 percent of individuals with Alagille syndrome have small deletions of genetic material on chromosome 20 that include the JAG1 gene. A few people with Alagille syndrome have mutations in a different gene, called NOTCH2.
    