Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Metachromatic leukodystrophy ?
    ### Response:
    Metachromatic leukodystrophy is an inherited condition characterized by the accumulation of fats called sulfatides in cells, especially cells of the nervous system. This accumulation results in progressive destruction of white matter of the brain, which consists of nerve fibers covered by myelin.
    