Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to tyrosine hydroxylase deficiency ?
    ### Response:
    Mutations in the TH gene cause TH deficiency. The TH gene provides instructions for making the enzyme tyrosine hydroxylase, which is important for normal functioning of the nervous system. Tyrosine hydroxylase takes part in the pathway that produces a group of chemical messengers (hormones) called catecholamines.
    