Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Prader-Willi syndrome ?
    ### Response:
    Prader-Willi syndrome is caused by the loss of function of genes in a particular region of chromosome 15. People normally inherit one copy of this chromosome from each parent. Some genes are turned on (active) only on the copy that is inherited from a person's father (the paternal copy).
    