What is Focal segmental glomerulosclerosis?
Focal segmental glomerulosclerosis (FSGS) is a rare kidney disease that causes scarring in the glomeruli, the tiny filtering units in the kidneys. The condition gets its name from the pattern of damage it creates – “focal” means it affects only some glomeruli, while “segmental” indicates that only portions of affected glomeruli show scarring (sclerosis). FSGS primarily affects children and young adults, though it can occur at any age, and disproportionately impacts people of African descent. With an incidence of approximately 7 cases per million people per year, FSGS is a leading cause of nephrotic syndrome and can progress to kidney failure if left untreated.
Key statistics
| Incidence: | ~7 per million per year |
| Age of onset: | Most common in children and young adults |
| Progression to kidney failure: | 50-80% within 5-10 years without treatment |
| Ethnic predisposition: | 3-5 times higher in people of African descent |
Symptoms
Swelling (edema), protein in urine (proteinuria), low blood protein levels (hypoalbuminemia), high cholesterol, fatigue, foamy urine, weight gain from fluid retention.
The hallmark symptom of FSGS is swelling that typically begins around the eyes and face, particularly noticeable in the morning, before progressing to the legs, ankles, and abdomen. Patients often notice their urine becomes foamy or frothy due to high levels of protein being lost through the kidneys. This protein loss leads to hypoalbuminemia, causing fluid to accumulate in tissues rather than staying in blood vessels. As the condition progresses, people may experience significant weight gain from fluid retention, persistent fatigue, and shortness of breath. High cholesterol levels often accompany these symptoms as the liver attempts to compensate for protein loss by producing more proteins and lipids. Some patients may also develop high blood pressure as kidney function deteriorates.
Causes and risk factors
FSGS has three main categories of causes. Primary (idiopathic) FSGS has no identifiable underlying cause and accounts for about 80% of cases. Genetic FSGS results from mutations in genes that affect podocyte function, including NPHS1, NPHS2, CD2AP, TRPC6, and ACTN4 genes, among others. This form follows various inheritance patterns including autosomal recessive and autosomal dominant. Secondary FSGS develops as a consequence of other conditions such as HIV infection, heroin use, obesity, sickle cell disease, reflux nephropathy, or certain medications including pamidronate and lithium.
Risk factors include family history of kidney disease, African ancestry, obesity, viral infections (particularly HIV), drug use (especially heroin), and certain genetic variants. Environmental factors such as exposure to toxins or infections may trigger the disease in genetically susceptible individuals.
Prevention
For genetic forms of FSGS, no prevention strategies exist beyond genetic counseling and testing for at-risk family members. Carrier testing is available for known familial mutations, and preimplantation genetic diagnosis may be an option for families with identified genetic variants. Secondary FSGS prevention focuses on managing underlying conditions – maintaining HIV viral suppression, avoiding nephrotoxic drugs, achieving healthy weight, and managing conditions like diabetes and hypertension that can damage kidneys. Regular monitoring of kidney function through urinalysis and blood tests may help detect early disease in high-risk individuals, though universal screening is not currently recommended.
Complications
Without treatment, FSGS frequently progresses to end-stage kidney disease, with 50-80% of patients developing kidney failure within 5-10 years. The massive protein loss characteristic of FSGS leads to increased risk of infections due to loss of immunoglobulins, blood clots from loss of anticoagulant proteins, and severe malnutrition. Cardiovascular complications are common and include accelerated atherosclerosis, heart attacks, and strokes, partly due to persistent high cholesterol and hypertension. Bone disease may develop from altered calcium and phosphorus metabolism as kidney function declines. Children with FSGS may experience growth retardation and developmental delays if the condition is not adequately controlled.
Diagnosis
FSGS diagnosis requires kidney biopsy showing the characteristic pattern of segmental sclerosis in some but not all glomeruli. Initial evaluation includes comprehensive metabolic panel showing elevated creatinine and blood urea nitrogen, urinalysis revealing significant proteinuria (often >3.5 grams per day), and 24-hour urine collection to quantify protein loss. Blood tests typically show hypoalbuminemia (Treatment
First-line treatment typically involves corticosteroids, with prednisone given at high doses (1mg/kg/day) for 4-6 months in children and adults who can tolerate this regimen. For steroid-resistant cases or those who cannot tolerate steroids, immunosuppressive agents include cyclosporine, tacrolimus, mycophenolate mofetil, and rituximab. Supportive care includes ACE inhibitors or ARBs such as lisinopril or losartan to reduce proteinuria and blood pressure. Diuretics like furosemide help manage edema, while statins address hyperlipidemia. For patients progressing to kidney failure, renal replacement therapy through dialysis or kidney transplantation becomes necessary. Novel treatments under investigation include complement inhibitors and podocyte-specific therapies. Genetic forms may require different treatment approaches, with some showing poor response to immunosuppressive therapy.
Prognosis
Prognosis varies significantly based on response to initial treatment and underlying cause. Patients achieving complete remission (proteinuria Quality of life
Living with FSGS requires significant lifestyle adaptations, particularly regarding diet and fluid management. Patients often need to follow a low-sodium diet (less than 2-3 grams daily) to help control swelling and blood pressure, while maintaining adequate protein intake to counteract losses. Regular monitoring of weight helps detect fluid retention early. Exercise should be encouraged but may need modification during active disease phases when fatigue and swelling are prominent. Mental health support is crucial, as the chronic nature of the disease, dietary restrictions, and medication side effects can lead to depression and anxiety. Many patients benefit from counseling and support groups. Work and school accommodations may be necessary during flares or treatment periods, particularly when high-dose steroids cause mood changes and cognitive effects. Maintaining social connections and pursuing adapted hobbies and interests helps preserve emotional well-being throughout the treatment journey.
Pregnancy and fertility
FSGS can significantly impact pregnancy outcomes, with increased risks of preeclampsia, premature delivery, and fetal growth restriction. Women with active disease or reduced kidney function should receive preconception counseling to optimize disease control before pregnancy. Many immunosuppressive medications require adjustment or discontinuation during pregnancy – mycophenolate is teratogenic and must be stopped, while tacrolimus and certain other agents may be continued under careful monitoring. Genetic counseling is essential for patients with hereditary forms of FSGS, as inheritance patterns vary from autosomal recessive to autosomal dominant. Some couples may benefit from preimplantation genetic diagnosis if specific mutations are identified. Fertility may be affected by chronic kidney disease and certain medications, though many patients can achieve successful pregnancies with appropriate planning and monitoring.
Children
Pediatric FSGS often presents more aggressively than adult-onset disease and has higher rates of steroid resistance. Children typically receive more intensive immunosuppressive protocols and longer steroid courses when responsive. Growth monitoring is crucial, as both the disease and treatments (particularly steroids) can impair normal development. School accommodations may be necessary during treatment periods, and psychosocial support helps children cope with a chronic condition. Genetic testing is particularly important in pediatric cases, as hereditary forms are more common in children than adults. Family screening may be indicated based on genetic results. Transition planning to adult care should begin in adolescence to ensure continuity of specialized care.
When to see a doctor
Seek immediate medical attention for sudden onset of severe swelling, especially facial swelling, difficulty breathing, chest pain, or signs of infection such as fever. Schedule urgent appointments for blood in urine, significantly foamy urine persisting more than a few days, rapid weight gain (more than 2-3 pounds in a day), or severe fatigue with swelling. Routine follow-up is needed for monitoring proteinuria, kidney function, and medication side effects. Patients on immunosuppressive therapy should promptly report any signs of infection, unusual bruising, or new symptoms.
Regional context
Limited data exists on FSGS prevalence in the Caucasus region (Georgia, Armenia, Azerbaijan) and Eastern Mediterranean countries. The condition likely occurs at similar rates to global averages, though genetic founder effects might influence specific mutation frequencies in isolated populations. Regional kidney disease registries would help establish accurate prevalence data. Healthcare infrastructure and access to specialized nephrology care, genetic testing, and immunosuppressive medications may vary across the region. We invite contributions from regional medical professionals to help establish more comprehensive epidemiological and clinical data for this area.
Research and clinical trials
Current research focuses on novel therapeutic targets including complement inhibition, podocyte regeneration, and precision medicine based on genetic subtypes. Clinical trials are investigating sparsentan (dual endothelin/angiotensin receptor antagonist), complement inhibitors like avacopan, and cell-based therapies. Gene therapy approaches are in early development for specific genetic forms. Recent breakthroughs include better understanding of podocyte biology and identification of new genetic causes. Patients can find current trials through ClinicalTrials.gov using search terms “FSGS” or “focal segmental glomerulosclerosis.” Biomarker research aims to predict treatment response and disease progression more accurately.
Frequently asked questions
Is FSGS hereditary?
About 10-15% of FSGS cases are hereditary, caused by mutations in genes affecting kidney filter cells. The majority of cases are not inherited but occur spontaneously or due to other underlying conditions.
Can FSGS be cured?
While there’s no definitive cure, many patients achieve remission with treatment, meaning protein levels normalize and kidney function stabilizes. Early diagnosis and treatment significantly improve the chances of remission.
Will I need dialysis or a kidney transplant?
About 50-80% of patients with untreated FSGS progress to kidney failure within 5-10 years. However, patients who respond well to treatment often maintain good kidney function long-term. If transplantation becomes necessary, outcomes are generally good.
How does FSGS affect daily life?
During active disease, patients may experience significant swelling, fatigue, and dietary restrictions. With successful treatment, many people return to normal activities, though regular medical monitoring and medications continue.
Can children with FSGS live normal lives?
Many children with FSGS who respond to treatment can participate in normal childhood activities, attend school regularly, and develop normally. However, ongoing medical care and some activity modifications may be necessary.
Support and resources
NephCure Kidney International: https://nephcure.org – Leading patient advocacy organization for FSGS and other rare kidney diseases
National Organization for Rare Disorders (NORD): https://rarediseases.org
Orphanet: https://orpha.net – Comprehensive rare disease database
EURORDIS: https://eurordis.org – European rare disease advocacy
National Kidney Foundation: https://kidney.org
American Society of Nephrology: https://asn-online.org
ClinicalTrials.gov: https://clinicaltrials.gov – Clinical trial database
Related conditions
Minimal change disease
Membranous nephropathy
IgA nephropathy
Nephrotic syndrome
Chronic kidney disease
Sources: Orphanet (orpha.net), OMIM, GeneReviews (NCBI), WHO ICD-11, relevant guidelines. Informational only; not medical advice. CC BY 4.0.
Cite this page
GMJ News Desk. “Focal segmental glomerulosclerosis.” GMJ News — Georgian Medical Journal, 2 June 2026. https://news.gmj.ge/condition/focal-segmental-glomerulosclerosis/
Licensed under CC BY 4.0. Free to share with attribution to GMJ News.Sources: Orphanet (orpha.net), OMIM, GeneReviews (NCBI), WHO ICD-11, EULAR/ACR guidelines. Schema.org MedicalCondition structured data included.
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