Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) metachromatic leukodystrophy ?
    ### Response:
    Metachromatic leukodystrophy is an inherited disorder characterized by the accumulation of fats called sulfatides in cells. This accumulation especially affects cells in the nervous system that produce myelin, the substance that insulates and protects nerves.
    