Predictive Determinants of Nephrotic Syndrome Remission in Patients With At-risk Polymorphism of APOL1

This is a multicentric retrospective observational cohort study. As primary objective, the study aims to evaluate the factors associated with nephrotic syndrome remission in patient with nephrotic syndrome, biopsy-prove minimal change disease or focal segmental glomerulosclerosis, and an at-risk variant of the APOL1 gene. As secondary objectives, this study aims: * To evaluate the benefit of corticosteroids in obtaining the remission of nephrotic syndrome * To identify the predictors of complete renal remission of nephrotic syndrome * To evaluate the benefit of corticosteroids in reducing the incidence of end-stage renal disease * To assess the adverse events of corticosteroids in patients treated with corticosteroids.