[In Process Citation]

Focal segmental glomerulosclerosis (FSGS) is a common histological diagnosis in adults with nephrotic proteinuria and one of the most frequent causes of end stage renal disease (ESRD) among the primary glomerulopathies. Renal histology reveals the "endpoint" of most glomerulopathies, whereby nephron loss results in functional overload and further damage of the remaining ones. FSGS is thus the clinico-pathological manifestation of genetical and acquired damages to the podocytes. Secundary FSGS is much more frequent than the primary ones. While secondary FSGS is characterized by slow progression of proteinuria and decline of kidney function, idiopathic FSGS presents already at first manifestation with renal insufficiency and nephrotic proteinuria with fast progression to ESRD. An etiological definition of FSGS is crucial for its management, since treatment of secundary forms is only symptomatic and if possibly causal, while immunosuppression is indicated in the cases of idiopathic FSGS. Primary FSGS presents a high risk of relapse after kidney transplantation.