Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) MECP2-related severe neonatal encephalopathy ?
    ### Response:
    MECP2-related severe neonatal encephalopathy is a neurological disorder that primarily affects males and causes brain dysfunction (encephalopathy). Affected males have a small head size (microcephaly), poor muscle tone (hypotonia) in infancy, movement disorders, rigidity, and seizures.
    