Bilateral Wilms' tumor in a child with Denys-Drash syndrome: novel frameshift variant disrupts the WT1 nuclear location signaling region.

Objectives: Wilm's Tumor (WT) is the most common pediatric kidney cancer. Whereas most WTs are isolated, approximately 5% are associated with syndromes such as Denys-Drash (DDS), characterized by early onset nephropathy, disorders of sex development and predisposition to WT.

Case Presentation: A 46,XY patient presenting with bilateral WT and genital ambiguity without nephropathy was heterozygous for the novel c.851_854dup variant in gene sequence. This variant affects the protein generating the frameshift p.(Ser285Argfs*14) that disrupts a nuclear localization signal (NLS) region.

Conclusions: This molecular finding is compatible with the severe scenario regarding the Wilm's tumor presented by the patient even though nephropathy was absent.