Focal segmental glomerulosclerosis (FSGS) is a disease in which scar tissue develops on the glomeruli, the small parts of the kidneys that filter waste from the blood. FSGS can be caused by a variety of conditions.

FSGS is a serious condition that can lead to kidney failure, which can only be treated with dialysis or kidney transplant. Treatment options for FSGS depend on the type you have.

Types of FSGS include:

  • Primary FSGS. Many people diagnosed with FSGS have no known cause for their condition. This is called primary (idiopathic) FSGS.
  • Secondary FSGS. Several factors, such as infection, drug toxicity, diseases including diabetes or sickle cell disease, obesity, and even other kidney diseases can cause secondary FSGS. Controlling or treating the underlying cause often slows ongoing kidney damage and might lead to improved kidney function over time.
  • Genetic FSGS. This is a rare form of FSGS caused by genetic changes. It is also called familial FSGS. It's suspected when several members of a family show signs of FSGS. Familial FSGS can also occur when neither parent has the disease but each one carries a copy of an altered gene that can be passed on to the next generation.
  • Unknown FSGS. In some cases, the underlying cause of FSGS cannot be determined despite the evaluation of clinical symptoms and extensive testing.


Focal segmental glomerulosclerosis can be caused by a variety of conditions, such as diabetes, sickle cell disease, other kidney diseases and obesity. It can also be caused by an infection and drug toxicity. A rare form of FSGS is caused by inherited abnormal genes. Sometimes there's no identifiable cause.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Focal segmental glomerulosclerosis (FSGS) care at Mayo Clinic

March 08, 2023
  1. Focal segmental glomerulosclerosis (FSGS). National Kidney Foundation. https://www.kidney.org/atoz/content/focal. Accessed July 10, 2021.
  2. Reiser J. Epidemiology, classification, and pathogenesis of focal segmental glomerulosclerosis. https://www.uptodate.com/contents/search. Accessed July 10, 2021.
  3. Yu ASL, et al. Primary glomerular disease. In: Brenner and Rector's The Kidney. 11th ed. Elsevier; 2020.
  4. Rosenberg AZ, et al. Focal segmental glomerulosclerosis. Clinical Journal of the American Society of Nephrology. 2017; doi:10.2215/CJN.05960616.
  5. Chebib FT (expert opinion). Mayo Clinic. Aug. 8, 2021.
  6. What is a kidney biopsy? National Kidney Foundation. https://www.kidney.org/atoz/content/kidney-biopsy. Accessed July 10, 2021.
  7. AskMayoExpert. Glomerular disease. Mayo Clinic; 2020.
  8. Cattran DC, et al. Treatment of primary focal segmental glomerulosclerosis. https://www.uptodate.com/contents/search. Accessed July 10, 2021.
  9. Braswell-Pickering EA. Allscripts EPSi. Mayo Clinic. July 15, 2021.

Focal segmental glomerulosclerosis (FSGS)