Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Primary hyperoxaluria type 2 ?
    ### Response:
    What causes primary hyperoxaluria type 2? Researchers have identified more than a dozen GRHPR mutations that cause this condition. These mutations either introduce signals that disrupt production of the glyoxylate reductase/hydroxypyruvate reductase enzyme or alter its structure.
    