Radio-ulnar synostosis in Williams syndrome. A frequently associated anomaly.

Limitation of supination and pronation of the forearm has been occasionally described in individuals with Williams syndrome. It was found in 26% of 23 subjects examined, and was associated with a spectrum of severity of radio-ulnar synostosis on radiography. The occurrence of this functional motor impairment in a substantial subset of persons with Williams syndrome is relevant, because its evaluation is important in habilitation planning.