Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Glycogen storage disease type 7 ?
    ### Response:
    Glycogen storage disease type 7 (GSD7) is an inherited condition in which the body is unable to break down glycogen (a complex sugar) in the muscle cells. Because glycogen is an important source of energy, this can interfere with the normal functioning of muscle cells.
    