Objectives: To establish syndrome-specific growth curves and growth rate (GR) curves for Williams syndrome (WS) and define the pattern of bone maturation and pubertal development.
Methods: In a prospective longitudinal study between 1990 and 1997, the growth data of 244 children with WS were collected: 295 values for GR were calculated for 74 girls and 331 values for 89 boys.
Results: Mean GR of children with WS was below normal by 1 to 2 cm/y in the first few years of life. One group of girls (n = 20) experienced an early pubertal growth spurt at age 9 years (maximal GR, 7.8 +/- 2.1 cm/y; menarcheal age, 10.4 +/- 1.4 years). A second group (n = 5) showed the growth spurt at age 11 years (7.5 +/- 1.1 cm/y; menarcheal age, 12.6 +/- 1.3 years). In boys, peak height velocity (8.7 +/- 2.3 cm/y) occurred at age 11 to 12 years. Bone age was delayed in both sexes during childhood and accelerated markedly during puberty. Final height was 152.4 +/- 5.7 cm in girls (n = 38) and 165.2 +/- 10. 9 cm in boys (n = 43).
Conclusions: The syndrome-specific GR curves for WS showed a premature and abbreviated pubertal growth spurt in both sexes. This growth spurt was directly related to bone age acceleration during puberty. The data from this longitudinal study provide an overview of both the dynamics of growth and its course in children with WS.