Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Mitochondrial neurogastrointestinal encephalopathy syndrome ?
    ### Response:
    Mitochondrial neurogastrointestinal encephalopathy (MNGIE) syndrome is a condition that particularly affects the digestive system and nervous system. Signs and symptoms of this condition most often begin by age 20 and worsen with time. Almost all people with MNGIE have gastrointestinal dysmotility, in which the muscles and nerves of the digestive system do not move food through the digestive tract efficiently.
    