Growth hormone treatment in young children with Down's syndrome:: effects on growth and psychomotor development

Background-Learning disability and short stature are cardinal signs of Down's syndrome. Insulin-like growth factor I (IGF-I), regulated by growth hormone (GH) from about 6 months of age, may be involved in brain development. Aims-To study long term effects of GH on linear growth and psychomotor development in young children with Down's syndrome; Study design-Fifteen children with Down's syndrome were treated with GH for three years from the age of 6 to 9 months (mean, 7.4). Linear growth, psychomotor development, skeletal maturation, serum concentrations of IGF;I and its binding proteins (BPs), and cerebrospinal fluid (CSF) concentrations of IGF-II were studied. Results-The mean height of the study group increased from -1.8 to -0.8 SDS (Swedish standard) during treatment, whereas that of a Down's syndrome control group fell from -1.7 to -2.2 SDS. Growth velocity declined after treatment stopped. Head growth did not accelerate during treatment. No significant difference in mental or gross motor development was found. The lour concentrations of serum IGF-I and IGFBP-3 became normal during GH treatment. Conclusions-GH treatment results in normal growth velocity in Down's syndrome but does not affect head circumference or mental or grass motor development. Growth velocity declines after treatment stops.