Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) C1q nephropathy ?
    ### Response:
    C1q nephropathy is a kidney disease in which a large amount of protein is lost in the urine. It is one of the many diseases that can cause the nephrotic syndrome. C1q is a normal protein in the immune system, and can be found floating in the circulation of most healthy people.
    