Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) intranuclear rod myopathy ?
    ### Response:
    Intranuclear rod myopathy is a disorder that primarily affects skeletal muscles, which are muscles that the body uses for movement. People with intranuclear rod myopathy have severe muscle weakness (myopathy) and poor muscle tone (hypotonia) throughout the body.
    