What is focal segmental glomerulosclerosis (FSGS)?

Focal segmental glomerulosclerosis (FSGS) is a rare disease that received its name because of how the affected kidney tissue looked under a microscope. Each of your kidneys contain about one million small filters. These filters are made up of a tuft of small blood vessels called a glomerulus. In FSGS, some but not all of the glomeruli (focal) are affected in one part of the glomerulus—known as a segment (segmental)—with the formation of a scar (also called sclerosis) leading to the name focal segmental glomerulosclerosis.

When this scarring happens, these tiny filters do not work properly. Proteins that are normally retained in the circulation are lost in your urine, excess fluid may be retained leading to swelling and the blood isn’t cleaned properly, which can cause symptoms of kidney failure.

Scarring of the glomeruli can also contribute to other health problems, such as high blood pressure and high cholesterol (elevated levels of fat in the blood). In some cases, FSGS causes permanent kidney damage or kidney failure.

How common is focal segmental glomerulosclerosis (FSGS)?

FSGS is a rare disease. Doctors diagnose it in about seven 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 people over 45 years old. It occurs more often in men than in women. Doctors diagnose it more often in African Americans than other ethnicities.

What causes focal segmental glomerulosclerosis (FSGS)?

Doctors classify focal segmental glomerulosclerosis (FSGS) based on its cause, but they do not always know what causes FSGS. The classifications of FSGS are often called:

• Primary FSGS: The condition develops on its own with no known cause.
• Genetic FSGS: The condition develops in someone who has a variation in one or more genes that is known to cause FSGS.
• Secondary FSGS: Other factors or underlying medical conditions can sometimes, but not always, cause FSGS.

Several factors that could cause secondary FSGS can include:

• Diseases including sickle cell anemia.
• 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.
• Obesity.

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

FSGS does not always cause symptoms you might notice on your own. Doctors often find signs or symptoms during a regular medical check or when testing for other issues.

When a large amount of protein is spilled in the urine due to FSGS, a group of signs and symptoms may occur together. This is a condition called nephrotic syndrome:

• Edema (fluid retention and swelling in the ankles, legs and face).
• High cholesterol.
• Lower than average amounts of albumin (a protein in the blood).
• Proteinuria (abnormally high levels of protein in the urine).
• Weight gain caused by extra fluids in the body.

How is focal segmental glomerulosclerosis (FSGS) diagnosed?

Several tests may lead your doctor to suspect a diagnosis of FSGS. These tests can include:

• Blood test: Taking a sample of blood to measure levels of protein 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 urine.

However, a definitive diagnosis of FSGS can only be made with a kidney biopsy.

• Kidney biopsy: Using a needle to take a small sample of tissue from the kidney for a lab to study for signs of FSGS under a microscope.

Sometimes, doctors use genetic testing to confirm 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 is not 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. Doctors aim to control symptoms to help you maintain a good quality of life and slow or prevent progressive scarring so that it does not lead to kidney failure.

In some people with secondary FSGS, treating the underlying condition may stop kidney damage from progressing. Doctors cannot repair glomeruli, but over time, kidney function may improve in these people.

Other treatments for FSGS include:

• Angiotensin-converting enzyme (ACE) inhibitors: Drugs that treat high blood pressure.
• Antibiotics: Medicines to treat infections.
• Diuretics: Medications that lower blood pressure and ridding the body of excess fluids.
• Immunosuppressive drugs: Drugs that manage the immune system response, such as cyclosporine and tacrolimus.
• Plasmapheresis: A procedure that decreases the number of antibodies by removing plasma (liquid) from the blood.
• Prednisone: A drug that lowers levels of protein in the urine.

What are the complications associated with focal segmental glomerulosclerosis (FSGS)?

FSGS can lead to high blood pressure and high cholesterol, and 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:

• Uncontrolled high blood pressure.
• Nausea, vomiting or loss of appetite.
• Swelling in the arms, legs or face.

How can you prevent focal segmental glomerulosclerosis (FSGS)?

You can take steps to reduce your risk of FSGS by:

• Maintaining a healthy weight.
• Treating conditions that can cause FSGS, such as infections and viruses.

Who is at risk of developing focal segmental glomerulosclerosis (FSGS)?

People at higher risk for FSGS include those who:

• Are African American.
• Are older than 45.
• Have a family member with the gene defect that causes FSGS.

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 does not get worse.

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

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

FSGS may not cause symptoms that you will notice on your own. Contact your healthcare provider if you experience unexplained swelling in your feet, legs or face.

What questions should I ask my doctor?

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

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