Mutations in the Wilm's tumor 1 (WT1) gene are associated with a wide spectrum of renal manifestations, ultimately leading to end‐stage kidney failure. There is an inadequate understanding of the molecular functions of WT1 in renal development, and this has limited the potential for therapeutic interventions in WT1‐related diseases. In this review, we discuss the existing data on the genetic and epigenetic abnormalities that have been described in WTs and their potential utility as biomarkers for risk stratification, prediction and prognosis in patients with WTs.