Previous studies reported reduced renal SIRT1 protein expression, especially in a model of diabetes, and these studies have examined the effect of proximal tubular SIRT1 and epigenetic regulation of claudin-1 in podocytes24,26,27 on diabetic kidney disease, but this interplay is still unclear in the context of nondiabetic FSGS, since tubular structures are not primarily affected in this condition. Here, SIRT1 is linked to focal segmental glomerulosclerosis.