Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) glycine encephalopathy ?
    ### Response:
    Glycine encephalopathy, which is also known as nonketotic hyperglycinemia or NKH, is a genetic disorder characterized by abnormally high levels of a molecule called glycine. This molecule is an amino acid, which is a building block of proteins. Glycine also acts as a neurotransmitter, which is a chemical messenger that transmits signals in the brain.
    