Genotype–phenotype analysis of pediatric patients with WT1 glomerulopathy

Background: WT1 is one of the genes commonly reported as mutated in children with steroid-resistant nephrotic syndrome (SRNS). We analyzed genotype–phenotype correlations in pediatric SRNS patients with WT1 mutations. Methods: From 2001 to 2015, WT1 mutations were detected in 21 out of 354 children with SRNS by genetic screening (5.9 %). The patients were grouped into missense (n = 11) and KTS splicing (n = 10) mutation groups. Results: Nine (82 %) patients with missense mutations presented with congenital/infantile nephrotic syndrome, while 8 (80 %) with KTS splicing mutations presented with childhood-onset SRNS. Progression to end-stage renal disease (ESRD) was noted in all patients with missense mutations (median age, 2.6 months; interquartile range [IQR], 0.8 months to 1.7 years) and in 5 patients with KTS splicing mutations (median, 9.3 years; IQR, 3.3–16.5 years). Disorders of sexual development (DSDs) were noted in all 12 patients with a 46, XY karyotype and in only 1 of the 8 patients with a 46, XX karyotype. One patient developed a Wilms tumor and another developed gonadoblastoma. Three patients had a diaphragmatic defect or hernia. Conclusions: WT1 mutations manifest as a wide spectrum of renal and extra-renal phenotypes. Genetic diagnosis is essential for overall management and to predict the genotype-specific risk of DSDs and the development of malignancies.