Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) tyrosine hydroxylase deficiency ?
    ### Response:
    Tyrosine hydroxylase (TH) deficiency is a disorder that primarily affects movement, with symptoms that may range from mild to severe.  The mild form of this disorder is called TH-deficient dopa-responsive dystonia (DRD). Symptoms usually appear during childhood.
    