Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Primary hyperparathyroidism ?
    ### Response:
    Hyperparathyroidism is an endocrine disorder in which the parathyroid glands in the neck produce too much parathyroid hormone (PTH). Signs and symptoms are often mild and nonspecific, such as a feeling of weakness and fatigue, depression, or aches and pains.
    