Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to phosphoglycerate dehydrogenase deficiency ?
    ### Response:
    Mutations in the PHGDH gene cause phosphoglycerate dehydrogenase deficiency. The PHGDH gene provides instructions for making the parts (subunits) that make up the phosphoglycerate dehydrogenase enzyme. Four PHGDH subunits combine to form the enzyme. This enzyme is involved in the production of the protein building block (amino acid) serine.
    