Five years of growth hormone treatment in children with Prader-Willi syndrome

The authors have followed 18 prepubertal children (3-12 years of age) with Prader-Willi syndrome during 5 years of growth hormone (GH) treatment. Init ially, all the children participated in a randomized, controlled GH trial, conducted to assess the effects of GH treatment on growth, body composition and behaviour. GH was administered to group A (n = 9) at a dose of 0.1 IU/ kg/day (0.033 mg/kg/day) for 2 years. Group B (n=9) was untreated for the f irst year, but the children were given GH at a dose of 0.2 IU/kg/day (0.066 mg/kg/day) during the second year. Thereafter, all children stopped GH tre atment for 6 months and were then restarted with GH at a dose of 0.1 IU/kg/ day (0.033 mg/kg/day). During the first year of GH treatment, there was a d ramatic increase in height SDS in both groups. The attained height percenti le was maintained during the continued GH treatment. Five years after the s tart of GH treatment, mean height SDS is still above average for age. Four children have reached final height, all within +/- 2 SD of target height. D uring the first year of GH treatment, body mass index (BMI) SDS decreased s ignificantly from 3.0 to 1.5 SDS in group A and from 2.8 to 1.2 SDS in grou p B, but it increased again during the 6-month period without treatment. Fo llowing the restart of GH treatment, BMI SDS has stabilized at 1.7 SDS for group A and 2.5 SDS for group B. In 16 of 18 patients, fasting insulin, glu cose and the Al, fraction of glycosylated haemoglobin remained within norma l ranges during 5 years of GH treatment. Following a period of rapid weight gain, two children have developed noninsulin-dependent diabetes mellitus. Glucose homeostasis returned to normal when GH treatment was withdrawn. In conclusion, GH treatment has a proven favourable effect on growth and body composition in patients with Prader-Willi syndrome. Treatment should be ind ividualized, and close surveillance of glucose homeostasis is needed, espec ially if the patient is severely obese.