Physical growth and development in patients with Rett syndrome.

Linear growth and sexual development was assessed in 21 girls who fulfilled the clinical criteria of Rett syndrome. Ten (48%) showed growth retardation with length or height below the 5th centile and an additional 8 (38%) had shifted their linear growth downward sometime during the first years of life. All the girls had age-appropriate sexual development with menarche in 6 at a mean age of 11 2/12 years. Early deceleration of linear growth, growth retardation and normal sexual development appear to be useful markers in the clinical definition of Rett syndrome.