In a larger study on a cohort of 141 patients with C3G or Ig-associated membranoproliferative glomerulonephritis (immune complex glomerulonephritis, ICGN), seven patients were positive for FBAAs, three were positive for anti-C3b IgG, and five were positive for both FBAA and anti-C3b. This evidence concerns the gene C3 and membranoproliferative glomerulonephritis.