Williams syndrome (WS) is a rare genetic disorder caused by a microdeletion on chromosome 7q11.23. While its cardiovascular and neurodevelopmental features have been extensively studied, genitourinary (GU) tract abnormalities remain underexplored. This study investigates the spectrum of GU anomalies and long-term outcomes in children with WS to enhance early detection and management strategies.

A longitudinal study was conducted from February 2019 to March 2025 on 42 children diagnosed with WS (22 males, 20 females). Patients underwent regular follow-ups every 3–6 months, including kidney and bladder ultrasounds, kidney function assessments (serum creatinine, estimated glomerular filtration rate [eGFR]), and urine analyses. Renal vascular Doppler scans were performed biannually in patients with positive findings and annually in those without. Long-term outcomes were evaluated based on renal function abnormalities, hypertension, recurrent urinary tract infections (UTIs), or obstruction.

Genitourinary tract abnormalities were identified in 69% (29/42) of patients (mean age: 17.5 ± 9.5 years). The detected anomalies included bladder diverticula (4.8%, 2/42), hypercalciuria (11.9%, 5/42), nephrocalcinosis (19%, 8/42), hydronephrosis (4.8%, 2/42), kidney stones (4.8%, 2/42), and simple kidney cysts (7.1%, 3/42). One patient had severe hypercalcemia with advanced nephrocalcinosis. Renal artery stenosis (RAS) was found in 47.6% (20/42) of patients, and 16.7% (7/42) had renal tubular acidosis requiring oral bicarbonate therapy. Among the two patients with bladder diverticula, one experienced recurrent UTIs and required surgical intervention, while the other remained asymptomatic under regular monitoring. During follow-up, the mean serum creatinine and eGFR levels were 0.6 ± 0.13 mg/dL and 106.4 ± 18.8 mL/min/1.73 m², respectively. No patients developed chronic kidney disease or progressive renal function decline. Hypertension was diagnosed in 19% (8/42) of cases, all requiring antihypertensive therapy. Recurrent UTIs occurred in 9.5% (4/42) of patients, with associated findings including bladder diverticula (50%), simple renal cysts (25%), and nephrocalcinosis (25%). No cases of acute obstruction due to kidney stones were recorded. Additionally, nephrocalcinosis resolved in 50% of affected patients, while the remainder remained stable.

Children with WS have a significantly increased risk of congenital and acquired GU abnormalities, emphasizing the importance of long-term renal surveillance. Routine ultrasound imaging of the GU tract and renal vessels, along with regular renal function monitoring and blood pressure assessment, should be integrated into standard WS care protocols to enable early intervention and prevent complications. Further research is needed to elucidate the genetic and pathophysiological mechanisms underlying these GU anomalies in WS.