Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Neuromyelitis Optica ?
    ### Response:
    Neuromyelitis optica (NMO) is an autoimmune disease of the central nervous system (CNS) that predominantly affects the optic nerves and spinal cord. It is sometimes also referred to as NMO spectrum disorder.In NMO, the body's immune system mistakenly attacks healthy cells and proteins in the body, must often those in the spinal cord and eyes.
    