Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Mitochondrial genetic disorders ?
    ### Response:
    Mitochondrial genetic disorders refer to a group of conditions that affect the mitochondria (the structures in each cell of the body that are responsible for making energy). People with these conditions can present at any age with almost any affected body system; however, the brain, muscles, heart, liver, nerves, eyes, ears and kidneys are the organs and tissues most commonly affected.
    