Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to congenital fibrosis of the extraocular muscles ?
    ### Response:
    CFEOM1 and rare cases of CFEOM3 result from mutations in the KIF21A gene. This gene provides instructions for making a protein called a kinesin, which is essential for the transport of materials within cells. Researchers believe that this protein plays an important role in the normal development and function of nerves in the head and face.
    