Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) hereditary xanthinuria ?
    ### Response:
    Hereditary xanthinuria is a condition that most often affects the kidneys. It is characterized by high levels of a compound called xanthine and very low levels of another compound called uric acid in the blood and urine. The excess xanthine can accumulate in the kidneys and other tissues.
    