[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Kidney](https://durgical.com/en/general-pathology/areas/kidney/) › Focal segmental glomerulosclerosis

# Focal segmental glomerulosclerosis

- Lesion

Podocyte loss leaves scars in parts of some glomeruli. It is a pattern with many causes and a common route to kidney failure.

Updated Nov 12, 2026

## Key points

- Biopsy can miss it: early lesions involve few glomeruli, starting at the corticomedullary junction.
- Primary FSGS: nephrotic, often with hematuria and hypertension, poorer steroid response than minimal change disease.
- Genes: NPHS1 (nephrin; congenital nephrotic syndrome of the Finnish type), NPHS2 (podocin), and APOL1 risk variants in people of African descent.
- Collapsing glomerulopathy: HIV-associated (HIVAN), COVID-associated, worst prognosis.
- Adaptive FSGS: reduced nephron mass, obesity, reflux nephropathy, sickle cell disease.

## What it is

FSGS means sclerosis in part of the tuft in only some glomeruli. It arises whenever podocytes are lost faster than they can be replaced: a primary podocytopathy related to minimal change disease, adaptive stress after loss of nephrons or in obesity, gene variants in slit diaphragm proteins or APOL1, viruses such as HIV and SARS-CoV-2, heroin and sickle cell disease. It is a leading cause of nephrotic syndrome in adults, especially in people of African or Hispanic descent.

## Structure

- Segments of the tuft collapse, with increased matrix, hyalinosis and foam cells; adhesion to Bowman capsule is common.
- IF: nonspecific trapping of IgM and C3 in the sclerotic segments.
- EM: foot process effacement, widespread in primary disease and patchy in adaptive disease; podocytes detach from the GBM.
- Collapsing variant: the whole tuft shrinks and podocytes swell and proliferate; tubules dilate into microcysts with protein casts.

## Step by step

- Podocytes are injured by a circulating factor, a gene defect, a virus or mechanical strain.
- They efface, detach and are lost in the urine; adult podocytes barely divide.
- Bare GBM sticks to Bowman capsule and plasma proteins seep into the wall (hyalinosis).
- Matrix accumulates and capillary loops collapse: a segmental scar.
- Remaining glomeruli enlarge and their pressure rises, injuring more podocytes.
- The cycle spreads the scars to more glomeruli and ends in global sclerosis.

## Clinical notes

- Proteinuria from nephrotic range to mild, plus hypertension and gradual loss of GFR.
- Primary FSGS can recur in a transplanted kidney, sometimes within hours.
- Adaptive FSGS has less edema and lower albumin than primary FSGS even with heavy proteinuria.

## Memory aid

Few glomeruli, part of each: when podocytes fall, the bare loops stick and scar.

## Test yourself

Think of the answer, then tap the question to see it.

## Why can a biopsy miss FSGS?

Early lesions involve only some glomeruli, mainly deep juxtamedullary ones, so a small sample may contain none.

## Which FSGS variant is linked with HIV infection?

Collapsing glomerulopathy, with tuft collapse, podocyte hyperplasia and microcystic tubules.

## What do APOL1 risk variants explain?

The higher risk of FSGS and chronic kidney disease in people of African descent; the variants protect against some trypanosomes.

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## Elsewhere in DurgiPedia

- [Glomerulus and the filtration barrier: podocytes, mesangium, JGA](https://durgical.com/en/histology/glomerulus-and-the-filtration-barrier-podocytes-mesangium-jga/)

## Connections

## Related 4

- [Minimal change disease](https://durgical.com/en/general-pathology/minimal-change-disease/)
- [Glomerular diseases: comparison table](https://durgical.com/en/general-pathology/glomerular-diseases-comparison-table/)
- [Chronic kidney disease and uremia](https://durgical.com/en/general-pathology/chronic-kidney-disease-and-uremia/)
- [Patterns of glomerular injury](https://durgical.com/en/general-pathology/patterns-of-glomerular-injury/)

## Related conditions 6

- [Focal segmental glomerulosclerosis](https://durgical.com/en/conditions/focal-segmental-glomerulosclerosis/)
- [Nephrotic syndrome](https://durgical.com/en/conditions/nephrotic-syndrome/)
- [HIV infection and AIDS](https://durgical.com/en/conditions/hiv-infection-and-aids/)
- [Obesity](https://durgical.com/en/conditions/obesity/)
- [Sickle cell disease](https://durgical.com/en/conditions/sickle-cell-disease/)
- [Chronic kidney disease](https://durgical.com/en/conditions/chronic-kidney-disease/)

## Microorganisms 1

- [Human immunodeficiency virus](https://durgical.com/en/microbiology/human-immunodeficiency-virus/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Focal segmental glomerulosclerosis: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000478.htm) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/focal-segmental-glomerulosclerosis/