Williams syndrome: features in late childhood and adolescence.

Nine children with the Williams syndrome were evaluated for physical, neurodevelopmental, and behavioral characteristics to record the natural history of this disorder. The study subjects, who ranged in age from 10 years to 20 years, generally showed lower than expected cognitive functioning with four of the nine functioning in the severely retarded range. However, all the children showed uneven developmental profiles, compared to measured IQ, with reading abilities exceeding the expected level and visual-motor skills deficient for overall performance expectations. All but one child had evidence of supravalvular aortic stenosis on echocardiography, but there was little morbidity from cardiovascular disease in this group of patients. Although all had grown at or below the fifth percentile in early childhood, seven now were above the fifth percentile for height. Personality attributes that characterize younger children with Williams syndrome persisted in this group of older children.