Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Graves' Disease ?
    ### Response:
    Graves disease, also known as toxic diffuse goiter, is the most common cause of hyperthyroidism in the United States. Hyperthyroidism is a disorder that occurs when the thyroid gland makes more thyroid hormone than the body needs.
                
The Thyroid

    