Primary IgA nephropathy is characterized with IgA-dominant deposition in the glomerulus [12]; in MN, the pathological characteristics is IgG-dominant deposits [13] mostly with C3 deposits [14], and IgM or IgA has also been reported in MN [15, 16]; normally, less immonoprotein depositions are found in the patients with MCD [17]; few researches find that IgA, IgM, C3 or C1q immune complex could also exist in MCD [18–20]. The gene discussed is C3; the disease is IgA glomerulonephritis.