Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) C1q deficiency ?
    ### Response:
    C1q deficiency is a rare disorder associated with recurrent skin lesions, chronic infections, systemic lupus erythematosus (SLE) or SLE-like diseases. It has also been associated with a kidney disease known as mesangial proliferative glomerulonephritis. C1q is a protein and together with other proteins, C1r and C1s, it forms the C1 complex.
    