Focal Segmental Glomerulosclerosis (FSGS)

What is focal segmental glomerulosclerosis (FSGS)?

Focal segmental glomerulosclerosis (FSGS) is a rare disease that causes scarring in your glomeruli, the tiny filters in your kidney. Each of your kidneys contain about 1 million glomeruli. The main job of glomeruli is to filter waste from your blood. They work just like a kitchen strainer. When blood circulates through glomeruli, the glomeruli keep the important parts your body needs. They strain out nutrients, minerals, extra fluid and waste products. The nutrients and minerals are sent back to your blood and the extra fluid and waste products become your pee. Kidney conditions that affect your glomeruli are called glomerular diseases. FSGS is just one of many types of glomerular diseases.

FSGS happens when small parts or sections of these tiny filters scar or harden (sclerosis). Of the damaged glomeruli, only some show scarring. When this scarring happens, it’s hard for your kidneys to act like a strainer. This can lead to kidney damage and, potentially, kidney failure. Treatment depends on what type of FSGS you have.

Here’s what the different parts of the name “focal segmental glomerulosclerosis’” mean:

• Focal: Some but not all glomeruli are affected.
• Segmental: Specific parts of the glomeruli have scarring.
• Sclerosis: Hardening.

The name ‘focal segmental glomerulosclerosis’ means hardening (sclerosis) of parts (segmental) of some (focal) glomeruli.

What are the different types of FSGS?

There are three types of focal segmental glomerulosclerosis:

1. Primary FSGS: There’s no known reason or obvious cause for having FSGS.
2. Secondary FSGS: This type occurs due to another disease or condition. Common causes could include infections, medications, drug use, sickle cell anemia or obesity. Controlling the underlying condition can often help treat secondary FSGS.
3. Genetic (familial) FSGS: This type happens due to genetics. This means you can have FSGS if your biological parents have the genetic mutation for FSGS. 

How common is focal segmental glomerulosclerosis (FSGS)?

FSGS is a rare disease. Healthcare providers diagnose it in about 7 out of 1 million people per year.

Who is affected by focal segmental glomerulosclerosis (FSGS)?

FSGS affects both adults and children but is most common in men and people assigned male at birth (AMAB) older than 45. Healthcare providers diagnose it most often in people who are Black.

What are the symptoms of focal segmental glomerulosclerosis (FSGS)?

FSGS doesn’t always cause symptoms you might notice on your own. Healthcare providers often find signs or symptoms during a routine exam or when testing for other medical conditions. Some of these signs and symptoms include:

• Edema (swelling in your arms, legs or face).
• High cholesterol.
• Lower-than-average amounts of albumin (a protein in your blood).
• Proteinuria (abnormally high levels of protein in your pee).
• Sudden weight gain caused by extra fluids in your body.
• High blood pressure (hypertension).

When you have edema, proteinuria and low albumin, your provider may call it nephrotic syndrome. Nephrotic syndrome causes your kidneys to release too much protein in your pee.

What causes focal segmental glomerulosclerosis (FSGS)?

There can be several different causes for FSGS. People who have primary FSGS often don’t have an obvious cause. Researchers believe that for unknown reasons, a protein in their blood damages part of the glomeruli.

Secondary FSGS happens when there’s too much blood flow to your glomeruli. Many factors can cause this, including:

• Diseases like sickle cell anemia, diabetes and lupus.
• Medications, such as interferons or bisphosphonates.
• Drugs such as heroin or anabolic steroids (substances used to enhance muscle growth).
• Infection, including viruses such as HIV.
• Having overweight or obesity.
• Other kidney conditions or having a congenital kidney condition. 

The genetic form of FSGS happens when the APOL1 gene mutates during fetal development. This may happen more commonly in people with ancestry from West Africa.

What are the complications of focal segmental glomerulosclerosis (FSGS)?

FSGS can lead to high blood pressure and high cholesterol. In some cases, FSGS can lead to kidney failure. This condition can be life-threatening and requires emergency medical treatment. Seek immediate care if you have FSGS and experience any of these symptoms of kidney failure:

• Unmanaged high blood pressure.
• Anemia.
• Nausea, vomiting or loss of appetite.
• Swelling in your arms, legs or face.

How is focal segmental glomerulosclerosis (FSGS) diagnosed?

Your healthcare provider will listen to your symptoms and take your medical history. Several types of kidney tests may help your provider diagnose FSGS. These tests can include:

• Blood test: Taking a sample of blood to measure levels of protein, waste and fat.
• Glomerular filtration rate (GFR): Checking a blood sample to measure how well your kidneys work.
• Urine test: Measuring the levels of blood and protein in your pee (urine).

However, providers can only definitively diagnose FSGS by doing a kidney biopsy. This is when a provider uses a needle to take a small sample of tissue from your kidney to look for signs of FSGS under a microscope.

Sometimes, healthcare providers use genetic testing to confirm a diagnosis of genetic FSGS. But because genetic tests can be expensive, and there are no known treatments for many forms of genetic FSGS, genetic testing isn’t common.

What are the treatments for focal segmental glomerulosclerosis (FSGS)?

Treatment for FSGS depends on the type and cause, your age and whether you have other health conditions. The goal of treatment is to manage your symptoms to help you maintain a good quality of life and slow scarring so that it doesn’t lead to kidney failure.

In some people with secondary FSGS, treating the underlying condition may stop kidney damage from progressing. Your healthcare provider can’t repair damaged glomeruli, but over time, kidney function may improve.

Some treatments for FSGS include:

• Angiotensin-converting enzyme inhibitors (ACE-Is).
• Angiotensin receptor blockers (ARBs).
• Mineralocorticoid receptor blockers (MRBs).
• Antibiotics.
• Diuretics.
• Immunosuppressive drugs.
• Plasmapheresis.
• Corticosteroids.

Your healthcare provider may also recommend changes to your diet and lifestyle. This could include things like:

• Limiting how much sodium (salt) and protein you eat.
• Exercising daily.
• Quitting smoking. (Your healthcare provider can also give you resources to help with this.)
• Taking certain vitamins.

Can focal glomerulosclerosis be cured?

FSGS is a chronic disease that can’t be undone or reversed. This means treatment can only slow the progression of kidney disease, not cure you from the disease. Everyone responds differently to treatment. Some people go on to need a kidney transplant or kidney dialysis to live.

How can you prevent focal segmental glomerulosclerosis (FSGS)?

Some forms of FSGS you can’t prevent. But you can take steps to reduce your risk of FSGS by:

• Maintaining a weight that’s healthy for you.
• Treating conditions that are known causes of FSGS.
• Seeing your healthcare provider for yearly checkups to keep an eye on your health.

What is the prognosis (outlook) for people with focal segmental glomerulosclerosis (FSGS)?

FSGS has no cure. The prognosis varies depending on the person. For some people, FSGS goes away on its own without treatment. For others, the disease continues for many years but doesn’t get worse.

Some people with FSGS develop kidney failure. They may need a kidney transplant or dialysis (a machine filters your blood instead of your kidneys). But many people with the disease live active, fulfilling lives. With regular checkups and blood tests, your provider will watch for any progression of the disease.

What is the life expectancy of someone with FSGS?

The life expectancy of people with FSGS varies depending on the severity of the disease. Remission is possible with treatment, and some people go on to live many years and enjoy a good quality of life. For people who don’t respond well to treatment, the disease can progress. One study found that on average, people who don’t respond to treatment enter end-stage kidney disease within six to eight years after their initial diagnosis. 

Is focal segmental glomerulosclerosis life-threatening?

Yes, it can be. Some people with FSGS go into kidney failure. But others can live several years with FSGS without it progressing to kidney failure.

When should I see a healthcare provider about focal segmental glomerulosclerosis (FSGS)?

FSGS may not cause symptoms that you’ll notice on your own. Contact your healthcare provider if you experience unexplained swelling in your feet, legs or face. This is often the first symptom of FSGS. You may also see foamy or bubbly pee in the toilet after you pee, due to high amounts of protein in your urine.

What questions should I ask my doctor?

If you have FSGS, you may want to ask your provider:

• What caused FSGS?
• What’s the best treatment for me?
• How long will treatment last?
• What signs of complications should I look out for?

A note from Cleveland Clinic

FSGS is a rare kidney disease that can cause kidney failure in some people. Luckily, there are treatments that can help stop this disease from progressing. While your kidneys won’t be 100% healthy again, you can go on to live a long and healthy life and enjoy doing things you love. It’s important to talk to your healthcare provider if you notice any swelling in your feet, legs or hands. Other signs like an irregular urine test can alert your provider to problems with your kidneys. Be sure to ask your provider any questions you have about FSGS.