Clinical and laboratory features that differentiate familial from sporadic focal segmental glomerulosclerosis in adolescents and adults

Background: Focal segmental glomerulosclerosis (FSGS) is an important cause of end-stage kidney disease in children and adults. Although most cases are sporadic (s), familial (f) presentation is also described. The purpose of the present study was to establish clinical and laboratory profiles of fFSGS vs. primary sFSGS, contributing to the distinguishing diagnosis in clinical practice and best management, in particular when mutation analysis is not available. Methods: Demographic, clinical and laboratorial parameters were studied in 124 patients 12 years and older with FSGS, subdivided in sFSGS (n=89) and fFSGS (n=35). Results: General and clinical features were similar, as well as serum creatinine at disease presentation. Proteinuria levels were more frequently ≥ 3g/day in sFSGS (63.8%) than in fFSGS (44%, p=0.080), and serum albumin levels were < 3.0 g/dL in 45.8% and 20%, respectively (p=0.046). The groups were statistically different regarding steroid resistance, corresponding to 60% in sFSGS and 100% in fFSGS (p=0.001). Conclusions: The studied groups were clinically similar, except that proteinuria tended to be higher (nephrotic range) and serum albumin was lower in sFSGS vs. fFSGS. In addition, all treated fFSGS patients were steroid resistant. At presentation it is important to characterize if the patient has fFSGS, that will contribute to further disease management, and disease history will be the first clue for such differential diagnosis.