Li-Fraumeni Syndrome-Associated p53 Variants Disrupt Kidney and Urinary Tract Development

Li-Fraumeni Syndrome (LFS) is a rare autosomal dominant disorder that increases the risk of various types of cancer. It is primarily caused by inherited mutations in the TP53 gene. While the tumor suppressor function of p53 is well established, its role in embryonic development, particularly in the formation of the kidney and urinary tract, remains poorly understood. Moreover, its contribution to human congenital anomalies has not been clearly defined. Here, we report that pathogenic TP53 variants can lead to congenital anomalies of the kidney and urinary tract (CAKUT), as well as genital defects (GD), in individuals with LFS. Among 28 unrelated TP53 mutation carriers, 28% (8/28) exhibited CAKUT and/or GD, with a higher frequency observed in individuals carrying structurally disruptive or dominant-negative mutations. We focused on two clinically observed variants: R242W, which destabilizes protein structure, and R282W, a dominant-negative hotspot mutation. AlphaFold modeling showed that both variants cluster within the DNA-binding domain and are predicted to disrupt tetramer formation. In Xenopus laevis, tp53 is expressed in developing nephric structures, consistent with findings from mouse models of nephrogenesis. Expression of either mutant TP53 mRNA in Xenopus embryos disrupted kidney morphogenesis in vivo, supporting a developmental loss-of-function effect. These findings indicate that pathogenic TP53 variants contribute to renal and urogenital defects in LFS. They reveal a previously unrecognized developmental role for p53 and expand the phenotypic spectrum associated with this cancer predisposition syndrome.