Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to pyruvate kinase deficiency ?
    ### Response:
    Pyruvate kinase deficiency is caused by mutations in the PKLR gene. The PKLR gene is active in the liver and in red blood cells, where it provides instructions for making an enzyme called pyruvate kinase. The pyruvate kinase enzyme is involved in a critical energy-producing process known as glycolysis.
    