Pelvic hypoplastic kidney in a patient with Williams-Beuren syndrome.

Renal and renovascular abnormalities constitute features of the Williams-Beuren syndrome (WBS), one multisystem genetic disorder in childhood, caused by a microdeletion of chromosome 7. We report a 12 years old boy who was diagnosed with WBS and had an ectopic pelvic hypoplastic left kidney, detected by ultrasonography and renal scintigraphy. Dystopic hypoplastic kidney is an infrequent finding in patients with WBS and our report showed the importance of a complete clinical and laboratory study of renal function in WBS.