Statural growth in Williams-Beuren syndrome.

The spontaneous growth of 165 patients (75 girls and 90 boys) with Williams-Beuren syndrome was analysed in a mixed longitudinal and cross-sectional manner. Mean (+/- 1 SD) length at birth was 48.2 +/- 2.6 cm in girls (n = 52) and 49.0 +/- 3.0 cm in boys (n = 65). Intrauterine growth retardation (length below -2 SD of the normal population) was present in 35% of the girls and 22% of the boys. Poor growth was noted during the first 2 years of life. Until age 9 years in girls and 11 years in boys, mean growth followed the 3rd percentile. A pubertal growth spurt with normal growth rate was seen at age 10 years in girls and 13 years in boys, i.e. 1 to 2 years earlier than normal. Menarche also occurred earlier than normal at a mean age of 11.6 +/- 1.5 years (n = 28). Mean adult height was 153.9 +/- 6.9 cm in girls (n = 17) and 168.2 +/- 6.9 cm in boys (n = 27), approximately corresponding to the 3rd percentile in both sexes and correlating with the genetic height potential (target height). The mean deficit of adult height compared to target height was 10.2 cm in girls and 9.1 cm in boys. Skeletal development progressed at an approximately normal rate in both sexes.