Focal Segmental Glomerulosclerosis (FSGS)

Focal Segmental Glomerulosclerosis (FSGS) is a kidney condition that affects the tiny filtering units called glomeruli. In this disease, some parts of the glomeruli become scarred, which reduces the kidney's ability to filter blood properly. This scarring can lead to protein leaking into the urine, causing swelling and other symptoms. The condition primarily affects the renal system and can lead to chronic kidney disease if untreated. It often causes high levels of proteinuria and may progress to kidney failure over time. The damage is usually patchy, affecting only some glomeruli and parts of those glomeruli, which is why it is called focal and segmental.

Focal Segmental Glomerulosclerosis (FSGS) is a histopathologic pattern of glomerular injury characterized by segmental sclerosis and hyalinosis affecting some but not all glomeruli. It results from podocyte injury leading to podocyte depletion, foot process effacement, and subsequent glomerular scarring. FSGS can be primary (idiopathic) or secondary to conditions such as HIV infection, heroin use, obesity, or genetic mutations (e.g., in NPHS1 or ACTN4). Clinically, it presents with nephrotic syndrome, including heavy proteinuria, hypoalbuminemia, edema, and hyperlipidemia. It is a major cause of nephrotic syndrome in adults and can progress to end-stage renal disease. The pathogenesis involves disruption of the glomerular filtration barrier, particularly the podocyte layer, leading to leakage of plasma proteins.