Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes IgA Nephropathy ?
    ### Response:
    Scientists think that IgA nephropathy is an autoimmune kidney disease, meaning that the disease is due to the bodys immune system harming the kidneys.
                
People with IgA nephropathy have an increased blood level of IgA that contains less of a special sugar, galactose, than normal.
    