Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Cockayne syndrome ?
    ### Response:
    Cockayne syndrome is a rare disorder characterized by short stature and an appearance of premature aging. Features of this disorder include a failure to gain weight and grow at the expected rate (failure to thrive), abnormally small head size (microcephaly), and impaired development of the nervous system.
    