Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Neurofibromatosis ?
    ### Response:
    Neurofibromatosis is a genetic disorder of the nervous system. It mainly affects how nerve cells form and grow. It causes tumors to grow on nerves. You can get neurofibromatosis from your parents, or it can happen because of a mutation (change) in your genes.
    