Nephrological findings and genotype-phenotype correlation in Beckwith-Wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS), an overgrowth disorder with several congenital abnormalities, encompasses nephrourological anomalies. The objective of the report is to analyze the latter and related genotype-phenotype correlations. The study was a retrospective review of nephrourological investigations and genotype in 67 BWS patients. Imaging and laboratory studies have been correlated with the molecular anomalies typical of BWS. Thirty-eight (56.7%) patients had a total of 61 nonmalignant nephrourological findings, including nephromegaly (n=24), collecting system abnormalities (n=14), cryptorchidism (n=11), nephrolithiasis (n=5), cysts (n=5), and dysplasia (n=1). Four patients had Wilms' tumor, all associated with renal hyperplasia. Renal findings were almost consistent in the BWS^IC1 group, with nephromegaly in all patients and collecting system abnormalities in half of them. BWS^UPD and negative patients also had frequent anomalies (63.6% and 61.9% respectively), whereas only 36.0% of BWS^IC2 had renal findings (p= 0.003). Cryptorchidism was associated with abdominal wall defects (pIC2 (p= 0.028). Urinary tract infections were observed in 17.9% of patients, with two resulting in life-threatening sepsis. Hypercalciuria was present in 10% of cases. 55.5% of BWS patients have renal findings. Although variegate, these anomalies disclose a genotype-phenotype correlation.