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.