Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to glycogen storage disease type 0 ?
    ### Response:
    Mutations in the GYS1 gene cause muscle GSD 0, and mutations in the GYS2 gene cause liver GSD 0. These genes provide instructions for making different versions of an enzyme called glycogen synthase. Both versions of glycogen synthase have the same function, to form glycogen molecules by linking together molecules of the simple sugar glucose, although they perform this function in different regions of the body.
    