Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to adenine phosphoribosyltransferase deficiency ?
    ### Response:
    Mutations in the APRT gene cause APRT deficiency. This gene provides instructions for making APRT, an enzyme that helps to convert a DNA building block (nucleotide) called adenine to a molecule called adenosine monophosphate (AMP). This conversion occurs when AMP is needed as a source of energy for cells.
    