C3 Glomerulopathy (C3G) and Primary Immune Complex Membranoproliferative Glomerulonephritis (IC-MPGN)

C3G and primary IC-MPGN are rare, severe kidney diseases in which an important part of the immune system, known as the complement cascade, is overactive. This results in the excessive breakdown of a protein called C3,1 and its breakdown products become trapped in the kidney, causing inflammation and damage to the organ.1

Living with C3G

Although C3G is a distinct disease from primary IC-MPGN, the underlying cause and progression of the two diseases are remarkably similar.2,3 The signs and symptoms of C3G and primary IC-MPGN include blood in the urine (hematuria); dark foamy urine due to the presence of protein (proteinuria); edema (swelling), often in the legs, although any part of the body can be affected; high blood pressure; and decreased urine output.4

Without treatment, these rare diseases often lead to kidney failure within five to 10 years of diagnosis, requiring patients to go on dialysis or get a kidney transplant.5-7 Additionally, 90% of patients who previously received a kidney transplant will experience disease recurrence.8

Resources

References

  1. Genetics Home Reference. Available at: https://ghr.nlm.nih.gov/condition/c3-glomerulopathy. Accessed November 27, 2019.
  2. Noris M, Donadelli R, Remuzzi G. Autoimmune abnormalities of the alternative complement pathway in membranoproliferative glomerulonephritis and C3 glomerulopathy. Pediatr Nephrol. 2019 Aug;34(8):1311-1323.
  3. Cook HT. Evolving complexity of complement-related diseases: C3 glomerulopathy and atypical haemolytic uremic syndrome. Curr Opin Nephrol Hypertens. 2018 May;27(3):165-170.
  4. Complement 3 Glomerulopathy (C3G). National Kidney Foundation Website. https://www.kidney.org/atoz/content/complement-3-glomerulopathy-c3g. Accessed November 21, 2019.
  5. Smith RJH, et al. Nat Rev Nephrol. 2019;15(3):129-143.
  6. Servais A, et al. Kidney Int. 2012;82(4):454-464.
  7. Zand L, et al. J Am Soc Nephrol. 2014;25(5):1110-1117.
  8. Tarragón, B, et al. C3 Glomerulopathy Recurs Early after Kidney Transplantation in Serial Biopsies Performed within the First 2 Years after Transplantation. Clinical Journal of the American Society of Nephrology. August 2024; 19(8)1005-1015. doi: 10.2215/CJN.0000000000000474.