Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Multiple endocrine neoplasia type 2A ?
    ### Response:
    Multiple endocrine neoplasia type 2A (MEN 2A) is is an inherited disorder caused by mutations in the RET gene. Individuals with MEN 2A are at high risk of developing medullary carcinoma of the thyroid. About 50% will develop pheochromocytoma, a tumor of the adrenal glands which may increase blood pressure.
    