We report renal abnormalities found in four cases of Brachmann-de Lange syndrome (BDLS). In two there were nephrogenic tests and renal cortical cysts, a further case showed cortical cysts, and the fourth had dilated collecting ducts. The literature describing renal abnormalities in BDLS has been reviewed, and this includes a report of one individual with BDLS who developed Wilms tumor. The genetic basis of BDLS has not been elucidated, although a submicroscopic abnormality of chromosome 3 seems likely. Nephrogenic rests may be Wilms' tumor precursor lesions and are seen in syndromes associated with Wilms' tumors. Mutations of genes on chromosome 11 are the most common genetic abnormalities associated with Wilms' tumor, but other chromosomes have also been implicated. The frequency of renal abnormalities in the BDLS suggests that the involved gene may be important in renal development and also possibly in Wilms' tumors.