Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) congenital fiber-type disproportion ?
    ### Response:
    Congenital fiber-type disproportion is a condition that primarily affects skeletal muscles, which are muscles used for movement. People with this condition typically experience muscle weakness (myopathy), particularly in the muscles of the shoulders, upper arms, hips, and thighs.
    