Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Miyoshi myopathy ?
    ### Response:
    Miyoshi myopathy is a muscle disorder that primarily affects muscles away from the center of the body (distal muscles), such as those in the legs. During early to mid-adulthood, affected individuals typically begin to experience muscle weakness and wasting (atrophy) in one or both calves.
    