[The complex etiopathogenesis of focal segmental glomerulosclerosis].

Focal segmental glomerulosclerosis (FSGS) is a pathological spectrum subtended by heterogeneous etiologies. A good knowledge of FSGS and its causes should be included in the nephrologists' clinical background, as it deeply influences the subsequent management of the affected patients. In fact, while immunosuppressive treatment should be considered in idiopathic FSGS, the treatment of secondary forms should primarily aim at curing or containing the underpinning etiologic factors. Furthermore, in contrast to secondary FSGS, idiopathic FSGS tends to relapse after kidney transplantation. Although FSGS has a wide spectrum of etiologies, several pathogenetic "moments" are shared. Furthermore, recent studies have identified a pool of glomerular cells potentially capable of regenerating lost podocytes; these cells might represent a promising therapeutic target. The primary aim of this review is to describe the etiologic factors associated with FSGS, with a focus on the main pathogenetic mechanisms involved in its development.