Focal Segmental Glomerulosclerosis (FSGS): Symptoms, Causes, and What Treatment Involves
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
Focal segmental glomerulosclerosis (FSGS) is a kidney disease in which scar tissue develops in the glomeruli, the tiny filters that clean the blood. It causes swelling, fluid weight gain and foamy urine. A kidney biopsy can confirm it. Treatment depends on the type and cause, and because FSGS can lead to kidney failure, regular follow-up is essential. [3] [4]
What the research says
Only about 1 in 5 adults with FSGS reaches remission with treatment. A Cochrane review of 15 trials (560 participants), which studied people with steroid-resistant FSGS, notes that only about 20% of people with FSGS achieve a partial or complete remission of nephrotic syndrome with treatment and about half progress to kidney failure. In 4 pooled cyclosporin trials (231 participants), cyclosporin with or without prednisone may increase the chance of complete remission (RR 2.31, 95% CI 1.13 to 4.73), but the certainty of the evidence is low (Hodson et al., Cochrane Database of Systematic Reviews, 2022).
FSGS can return after a kidney transplant. Among 11,742 kidney transplant recipients screened, 176 had idiopathic FSGS as their original kidney disease. The disease came back in 57 of them (32%), and 39% of those lost their transplanted kidney over a median of 5 years. Recurrence was associated with a five-fold higher risk of graft loss, and partial or complete remission occurred in 57% of patients with recurrence (Uffing et al., Clinical Journal of the American Society of Nephrology, 2020).
What Is FSGS?
Your kidneys contain thousands of tiny filtering units called glomeruli. Healthy glomeruli remove waste from your blood to create urine [3].
FSGS results from scar tissue developing in the glomeruli. As the scarring spreads, kidney function gets worse [3].
The condition is serious. It can lead to kidney failure, which can only be treated with dialysis or a kidney transplant. Treatment options depend on the type of FSGS you have [3].
Symptoms: The Three Classic Warning Signs
FSGS usually announces itself through a small set of recognizable symptoms. The most common is edema, which is swelling in the legs and ankles, around the eyes and in other parts of the body. Fluid buildup can also cause weight gain. A third sign is foamy urine, caused by excess protein spilling into the urine (a condition called proteinuria) [3].
Symptom | What it looks like | What is happening |
|---|---|---|
Edema | Swelling in the legs, ankles and around the eyes | Fluid leaks into tissues as the filters break down |
Weight gain | From fluid buildup, not fat | The body holds on to salt and water |
Foamy urine | Proteinuria | Damaged filters let protein pass into the urine |
When to see a doctor: See a healthcare professional if you have any of these symptoms [3].
The Four Types of FSGS
Type | What it means | Key detail |
|---|---|---|
Primary FSGS (idiopathic) | No known cause | Many people diagnosed with FSGS have no known cause |
Secondary FSGS | Caused by another condition or factor | Infection, drug toxicity, diabetes, sickle cell disease, obesity and other kidney diseases |
Genetic FSGS (familial) | Caused by inherited gene changes | Rare; suspected when several family members show signs |
Unknown FSGS | The cause cannot be determined | Persists even after evaluation of symptoms and extensive testing |
One point worth knowing about secondary FSGS: controlling or treating the underlying cause often slows ongoing kidney damage and might lead to improved kidney function over time [3].
For genetic FSGS, the family pattern matters. It is suspected when several members of a family show signs of the disease. 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 [3].
Causes and Risk Factors
What causes FSGS?
FSGS can be caused by a variety of conditions and exposures [3]:
Diseases such as diabetes or sickle cell disease
Other kidney diseases
Obesity
Infections
Damage from illicit drugs, medicines or toxins
Inherited gene changes (in the rare genetic form)
Sometimes there is no known cause at all. This is called primary (idiopathic) FSGS [3].
Risk factors
Risk factor category | Examples |
|---|---|
Conditions that can damage the kidneys | Diabetes, lupus, obesity and other kidney diseases |
Certain infections | HIV and hepatitis C |
Gene changes | Certain genes passed through families |
Complications: Why FSGS Needs to Be Taken Seriously
FSGS may lead to other health concerns, including [3]:
Nephrotic syndrome. The body passes too much protein in the urine. Nephrotic syndrome raises the risk of other health conditions, such as blood clots and high blood pressure.
Kidney failure. Damage to the kidneys that can't be fixed causes the kidneys to stop working. The only treatments for kidney failure are dialysis or a kidney transplant.
How Is FSGS Diagnosed?
If FSGS is possible, your healthcare professional reviews your medical history and orders tests to see how well your kidneys work [4].
Test | What it measures |
|---|---|
Urine tests | A 24-hour urine collection measures the amount of protein and other substances in the urine |
Blood tests | The glomerular filtration rate (GFR) measures how well the kidneys remove waste from the body |
Kidney imaging | Ultrasound, CT or MRI scans show kidney shape and size; nuclear medicine studies also might be used |
Kidney biopsy | A needle is placed through the skin to take a tiny sample of the kidney; the results can confirm a diagnosis of FSGS |
Treatment Options
Treatment for FSGS depends on the type and the cause [4].
Medications
Depending on symptoms, medicines to treat FSGS might include [4]:
Medicine | What it does |
|---|---|
ACE inhibitor or ARB | Lowers blood pressure and reduces protein in the urine |
Cholesterol-lowering medicines | People with FSGS often have high cholesterol |
Diuretics | Help the body get rid of salt and water; can improve blood pressure and swelling |
Medicines that lower the immune response (for primary FSGS) | May stop the immune system from damaging the kidneys; they include corticosteroids, which can have serious side effects and are used with caution |
The long-term outlook
The disease may return. FSGS can come back even after treatment [4].
Scarring may be lifelong. Because scarring in the glomeruli might be permanent, you need to follow up with your healthcare team to check how well your kidneys work [4].
Kidney failure. For people who reach kidney failure, treatments include dialysis and kidney transplant [4].
Lifestyle and Home Care: Protecting Your Kidneys
These lifestyle changes can help keep the kidneys healthier [4]:
Avoid medicines that can damage your kidneys. These include some pain relievers such as nonsteroidal anti-inflammatory drugs (NSAIDs). Over-the-counter examples are ibuprofen and naproxen sodium.
Eat a healthy diet. To protect your kidneys and lower your blood pressure, limit salt and protein.
Don't smoke. If you need help quitting, talk with a member of your healthcare team.
Stay at a healthy weight. Lose weight if you are overweight.
Be active on most days. Ask your healthcare team what types and how much exercise you can do.
Preparing for Your Appointment
You may start by seeing your primary healthcare professional, or you may be referred to a nephrologist, a specialist in kidney conditions [4].
What you can do
When you make the appointment, ask whether you need to do anything beforehand, such as fasting (not eating or drinking) before certain tests. Make a list of:
Your symptoms, including any that seem unrelated, and when they began
Key personal information, including major stresses, recent life changes and family medical history
All medicines, vitamins and supplements you take, with doses
Questions to ask your healthcare team
Take a family member or friend along, if possible, to help you remember the information you are given.
Questions to ask your healthcare professional
What's likely causing my symptoms?
What are other possible causes for my symptoms?
What tests do I need?
Is my condition likely to go away or be long-lasting?
What are my treatment choices?
I have other health conditions. How can I best manage them together?
Are there restrictions I need to follow?
Should I see a specialist?
Are there brochures or other printed material I can have? What websites do you think might be helpful?
What to expect from your doctor
Your healthcare professional is likely to ask:
Do your symptoms come and go, or are they constant?
How severe are your symptoms?
What, if anything, seems to make your symptoms better?
What, if anything, seems to make your symptoms worse?
Conclusion
FSGS is a serious kidney condition, but the type and the underlying cause largely shape what treatment can do. If you notice swelling, unexplained weight gain or foamy urine, see a healthcare professional. A kidney biopsy can confirm the diagnosis, and treatment, whether blood pressure medicines, diuretics, immune-lowering medicines or lifestyle changes, aims to slow damage and protect the kidney function you have [3][4].
Because FSGS may return and scarring might be lifelong, ongoing follow-up with your care team is essential. Your next step: if any of the symptoms described here sound familiar, book an appointment with your healthcare professional. Early evaluation and consistent follow-up give treatment the best chance of working.
Frequently Asked Questions
What does FSGS stand for?
FSGS stands for focal segmental glomerulosclerosis, a kidney disease in which scar tissue develops in the glomeruli, the tiny structures inside the kidneys that filter waste from the blood to create urine. [3]
What are the main symptoms of FSGS?
The three classic symptoms are swelling (edema) in the legs and ankles and around the eyes, weight gain from fluid buildup, and foamy urine caused by excess protein in the urine (proteinuria). See a healthcare professional if you have any of these. [3]
Is FSGS curable?
Because scarring in the glomeruli might be permanent, FSGS needs long-term follow-up. In secondary FSGS, controlling or treating the underlying cause often slows ongoing kidney damage and might improve kidney function over time, while other treatments aim to ease symptoms and protect kidney function. [3][4]
What are the four types of FSGS?
Primary FSGS has no known cause. Secondary FSGS is caused by another condition or exposure, such as diabetes, sickle cell disease, obesity, infection or drug toxicity. Genetic (familial) FSGS is caused by inherited gene changes. Unknown FSGS is when no cause can be found despite extensive testing. [3]
Can FSGS be inherited?
Yes, in the rare genetic form. Familial FSGS is suspected when several family members show signs of the disease. It can also occur when neither parent has the disease but each carries a copy of an altered gene that can be passed on. [3]
How is FSGS diagnosed?
Through your medical history and tests: urine tests (including a 24-hour urine collection), blood tests (glomerular filtration rate), kidney imaging (ultrasound, CT or MRI) and a kidney biopsy, which can confirm the diagnosis. [4]
What medicines treat FSGS?
Depending on the type and symptoms, treatment may include ACE inhibitors or ARBs, diuretics, cholesterol-lowering medicines and, for primary FSGS, medicines that lower the immune response such as corticosteroids. [4]
Does FSGS come back after treatment?
FSGS can. FSGS is a disease that may return, and scarring in the glomeruli might be lifelong, so regular follow-up with your healthcare team is needed to check how well your kidneys work. [4]
What happens if FSGS leads to kidney failure?
The only treatments for kidney failure are dialysis or a kidney transplant, which is why early diagnosis and steady follow-up matter. [3][4]
References
Hodson EM, Sinha A, Cooper TE. Interventions for focal segmental glomerulosclerosis in adults. Cochrane Database of Systematic Reviews. 2022;2:CD003233. PMID 35224732. https://doi.org/10.1002/14651858.CD003233.pub3
Uffing A, Pérez-Sáez MJ, Mazzali M, et al. Recurrence of FSGS after kidney transplantation in adults. Clinical Journal of the American Society of Nephrology. 2020;15(2):247-256. PMID 31974287. https://doi.org/10.2215/CJN.08970719
Mayo Clinic. Focal segmental glomerulosclerosis (FSGS): Symptoms and causes. Mayo Clinic. January 31, 2025. https://www.mayoclinic.org/diseases-conditions/fsgs/symptoms-causes/syc-20354693
Mayo Clinic. Focal segmental glomerulosclerosis (FSGS): Diagnosis and treatment. Mayo Clinic. January 31, 2025. https://www.mayoclinic.org/diseases-conditions/fsgs/diagnosis-treatment/drc-20562383
Medical disclaimer
This article was prepared for general information only and is not a substitute for professional medical advice.
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