Focal segmental glomerulosclerosis (FSGS) is a disease in which scar tissue develops on the parts of the kidneys that filter waste out of the blood (glomeruli). FSGS can be caused by a variety of conditions. Without treatment, primary FSGS may lead to kidney failure where the only treatment options are dialysis or kidney transplant.

  • Experience. Mayo Clinic treats more than 500 people each year who have FSGS.
  • Expertise. The large number of kidney specialists (nephrologists) at Mayo Clinic allows doctors to subspecialize in specific aspects of kidney medicine, including glomerular diseases such as FSGS.
  • Teamwork. Kidney specialists work together with transplant specialists and other experts to develop the best treatment plan for you.
  • New ideas. Mayo is active in research to better understand FSGS and to test new therapies through the Mayo Nephrology Collaborative Group (MNCG). You may have the opportunity to participate in clinical trials of experimental treatments.
  • Coordinated care. Mayo doctors work closely with your local doctor to coordinate treatment and follow-up care.

In the early stages, you may have no symptoms of focal segmental glomerulosclerosis (FSGS). As the disease progresses, signs of nephrotic syndrome may appear. Nephrotic syndrome is a disease that causes your body to excrete too much protein in the urine.

Signs of this disease include:

  • A foamy appearance to your urine
  • High blood pressure
  • Swelling in your face, hands or legs

Other signs your doctor can identify include:

  • Large amount of protein (albumin) in your urine
  • Low level of protein in your blood
  • High level of cholesterol in your blood

Primary FSGS that is unresponsive to treatment will often progress over time to kidney damage and end-stage kidney disease. If your kidneys fail, you will die without either dialysis or a kidney transplant.

Types of FSGS include:

  • Primary FSGS. A significant number of people diagnosed with FSGS have no known cause for their condition. This is called primary (idiopathic) FSGS.
  • Secondary FSGS. This condition is brought on by any of several factors — for example, infection, drug toxicity, diseases such as diabetes or sickle cell disease, significant obesity, use of certain medications such as anabolic steroids, or other types of kidney diseases. Controlling or treating the underlying cause often improves kidney function.
  • Genetic (also called familial) FSGS. This rare form of FSGS is caused by genetic mutations. 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 carries one copy of an abnormal gene that can be passed on to the next generation. Therefore, even if the disease doesn't show up in other family members, it's possible that the disease may be inherited.

Read more about nephrotic syndrome.

Mayo Clinic in Rochester, Minn., ranks No. 1 for kidney disorders in the U.S. News & World Report Best Hospitals rankings. Mayo Clinic in Scottsdale, Ariz., and Mayo Clinic in Jacksonville, Fla., are ranked high performing for kidney disorders by U.S. News & World Report.

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If focal segmental glomerulosclerosis (FSGS) is suspected, your doctor will review your medical history and order lab tests to assess your kidney function. The usual tests are:

Kidney (renal) function or other testing

  • Estimated glomerular filtration rate (eGFR). To get an indication of how well your kidneys are removing waste from the blood, you may have a blood sample taken to calculate your eGFR. The eGFR estimates the percentage of kidney function you have left.
  • Blood and urine tests. Blood tests and an analysis of a 24-hour urine collection can determine protein levels and possibly identify an underlying cause of kidney dysfunction, such as infection or diabetes.
  • Iothalamate clearance test. Sometimes your doctor may order a more sophisticated test that uses a special contrast agent to track how well your kidneys filter waste. Mayo Clinic is one of the few centers to specialize in iothalamate clearance testing using a dedicated renal studies laboratory.
  • Imaging studies. In some cases, the cause of kidney dysfunction may be found by getting images of the kidneys using studies such an ultrasound test.

Kidney biopsy

Taking a tiny sample from your kidney using a needle (biopsy) is the most accurate test to confirm the diagnosis of many kidney diseases, including FSGS. Because of the large number of people they evaluate each day, Mayo Clinic specialists are very experienced with kidney biopsies.

Read more about kidney biopsy.

Successful treatment of focal segmental glomerulosclerosis (FSGS), and the nephrotic syndrome often associated with it, can be challenging. Your doctor may recommend:

  • Treating any identified causes of FSGS
  • Following a healthy diet that includes a strict low-sodium approach to help protect your kidneys and lower your blood pressure and limiting protein to a moderate amount
  • Using diuretic medications to help excrete salt and water, which can improve blood pressure and swelling
  • Avoiding medications that have the potential to damage your kidneys, for example, some pain relievers such as nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Taking an angiotensin-converting enzyme (ACE) inhibitor or an angiotension II receptor blocker to lower your blood pressure and decrease protein in your urine (proteinuria)
  • Treating high cholesterol
  • Taking a vitamin D supplement if your vitamin D level is found to be low
  • Taking anticoagulants if you've had a previous blood clot
  • Stopping smoking
  • Reducing body weight if you're overweight
  • Getting regular physical activity and exercise

Drugs to suppress your immune system are sometimes offered to people who can tolerate corticosteroids and immunosuppressive drugs, but this approach is not effective for everyone. These medications can have serious side effects.

Some people respond well to immunologic therapy, but FSGS is a disease that may relapse. Because scarring in the glomeruli may be permanent, follow-up monitoring is important to assess kidney function.

For people who progress to kidney failure, treatment options include:

  • Dialysis. Mayo Clinic offers state-of-the-art dialysis treatment, including the option for in-home dialysis.
  • Kidney transplant. All three Mayo campuses offer kidney transplants. Mayo has performed thousands of kidney transplants with above average results.

Read more about nephrotic syndrome treatment.

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

Specialists in nephrology and hypertension care for adults who have focal segmental glomerulosclerosis.

For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.

Specialists in nephrology and hypertension care for adults who have focal segmental glomerulosclerosis.

For appointments or more information, call the Central Appointment Office at 904-953-0853 8 a.m. to 5 p.m. Eastern time, Monday through Friday or complete an online appointment request form.

Doctors in the Glomerular Disease/Renal Parenchymal Disease Clinic specialize in caring for people who have focal segmental glomerulosclerosis.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

The Mayo Nephrology Collaborative Group (MNCG) develops and conducts studies aimed at treating people with renal parenchymal diseases, including FSGS. The MNCG is a consortium of nephrologists from Mayo Clinic in Minnesota, Florida and Arizona and from other centers across the United States interested in researching treatments for renal parenchymal diseases.

Mayo publications

See a list of publications by Mayo doctors on FSGS on PubMed, a service of the National Library of Medicine.

Mar. 20, 2014