The term focal segmental glomerulosclerosis (FSGS) describes a histological finding characterised by sclerosis. The lesions are "focal" in that they are seen in only a proportion of glomeruli and "segmental" because they involve only a portion of the glomerular tuft.
Glomerulosclerosis occurs in a number of settings and is the end-result of hyperfiltration injury. However it is also seen as a primary pathology causing full-blown nephrotic syndrome.
Primary idiopathic FSGS accounts for about 10% of childhood nephrotic syndrome and a small number of cases of congenital nephrotic syndrome. Inherited forms of primary FSGS have been identified, occurring as both autosomal dominant and recessive conditions.
FSGS tends to be steroid resistant, although some patients will respond to steroids, usually administered alongside other immunosuppressive drugs such as cyclophosphamide, cyclosporine, tacrolimus or mycophenolate mofetil.
Around 50% of children with FSGS will progress to end-stage renal failure.