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Focal segmental glomerulosclerosis, or FSGS, is a term that refers to a pattern of kidney damage in which there is scarring in some of the glomeruli (the filtering units of the kidneys that remove waste from blood). FSGS is classified as primary, secondary or genetic according to its cause. While primary FSGS has no known cause, secondary FSGS can be caused by or associated with many different underlying conditions. Genetic FSGS is rare and caused by pathogenic variants, also called genetic mutations. FSGS occurs most often in adults 45 or older, though children can also be affected. The condition is diagnosed slightly more often in males than females, and people of African descent are disproportionately affected. Primary symptoms include swelling, weight gain associated with fluid buildup, high cholesterol and high blood pressure. FSGS can result in kidney failure, necessitating a kidney transplant or dialysis. Though various treatments can improve a patient’s quality of life, there are currently no approved treatments specifically for FSGS.
- swelling, particularly in the legs, feet and ankles
- weight gain as a result of extra fluid buildup
- high cholesterol
- high blood pressure
- foamy or frothy urine caused by high levels of protein in the urine
Primary FSGS does not have a known cause. Secondary FSGS can have many different causes, including autoimmune disease, diabetes, sickle cell disease, other kidney diseases and obesity. In rare cases, FSGS is caused by pathogenic variants in one of many genes known to cause FSGS (this is known as genetic FSGS). Having a family member with FSGS may increase an individual’s chance of acquiring it.
How FSGS is diagnosed
In patients with symptoms of kidney dysfunction, a physician may order tests including a blood test to identify high levels of creatinine and a urine test to identify the presence of protein. A diagnosis of FSGS is confirmed by a kidney biopsy showing a characteristic pattern of scarring of the glomeruli (the filtering units of the kidneys that remove waste from blood).
Currently, there are no approved treatments specifically for FSGS, and treatment approaches depend on the cause. Depending on the cause, treatments may include steroids or immunosuppressive drugs to stop the immune system from attacking the glomeruli (the filtering units of the kidneys that remove waste from blood), blood pressure medications to reduce protein loss and control blood pressure, diuretics to help the body get rid of excess fluid and reduce swelling and diet changes, such as reducing salt intake to lessen the filtering workload for the kidneys. In the event of kidney failure, dialysis or a kidney transplant may be needed.
It’s difficult to evaluate the prevalence of FSGS worldwide due to differing indications and accessibility to resources like kidney biopsy, though evidence suggests this disease is becoming more common. In the United States, approximately 5,400 patients are diagnosed with FSGS every year, and Black Americans are at least four times more likely than white Americans to have FSGS. FSGS is one of the leading causes of end-stage kidney disease (ESKD) in children, and is associated with approximately 20% of all new cases of nephrotic syndrome — the name given to a group of symptoms caused by kidney dysfunction — in children each year.
There are many different conditions that can cause damage or dysfunction of the kidney’s glomeruli. These include autoimmune diseases, hereditary kidney diseases, viral or bacterial infections, among others. FSGS is one of many patterns of kidney disease involving the glomeruli.
- The American Kidney Fund
- NephCure Kidney International
- American Association of Kidney Patients
- National Kidney Foundation
- Kidney Research UK
- Kidney Foundation of Canada
The latest on our research
We are jumpstarting our FSGS program to accelerate research on the condition and welcome all patients interested in participating and spreading the word to the FSGS community.