Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to alkaptonuria ?
    ### Response:
    Mutations in the HGD gene cause alkaptonuria. The HGD gene provides instructions for making an enzyme called homogentisate oxidase. This enzyme helps break down the amino acids phenylalanine and tyrosine, which are important building blocks of proteins. Mutations in the HGD gene impair the enzyme's role in this process.
    