Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Yellow nail syndrome ?
    ### Response:
    Yellow nail syndrome is characterized by yellow nails that lack a cuticle, grow slowly, and are loose or detached (onycholysis). Yellow nail syndrome is often associated with diseases of the lung or lymphedema.  Yellow nail syndrome often affects older adults, though it can occur at any age.
    