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 (p < 0.001) appearing more frequently in BWS(IC2) (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.