In recent years, a new kind of MN was increasing in China, which showed cells proliferation, electron dense deposits deposited in multisite, and most of patients showed “full house” in immunofluorescence, that is IgG, IgA, IgM, C3, C1q positive, but without definite etiology such as systemic lupus erythematosus (SLE), hepatitis B virus (HBV) infection, or some other known causes in clinical, which caught people’s eyes gradually. This evidence concerns the gene C3 and systemic lupus erythematosus.