Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Stickler syndrome ?
    ### Response:
    Mutations in several genes cause the different types of Stickler syndrome. Between 80 and 90 percent of all cases are classified as type I and are caused by mutations in the COL2A1 gene. Another 10 to 20 percent of cases are classified as type II and result from mutations in the COL11A1 gene.
    