Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Pfeiffer syndrome ?
    ### Response:
    Pfeiffer syndrome results from mutations in the FGFR1 or FGFR2 gene. These genes provide instructions for making proteins known as fibroblast growth receptors 1 and 2. Among their multiple functions, these proteins signal immature cells to become bone cells during embryonic development.
    