Endocrine Abstracts

Introduction: Prader–Willi Syndrome (PWS) is a rare genetic disorder due to loss of paternally inherited genes on chromosome 15q11-13. It is characterised by neonatal hypotonia, childhood obesity, hypogonadism, cognitive and behavioural disabilities, and development of scoliosis. We aimed to review the impact of growth hormone (GH) doses, scoliosis and IGF1 levels on height gain in children with PWS.

Methods/design: Retrospective observational study of thirty-eight children with PWS on GH, from a tertiary paediatric centre, with up to 10 years follow-up. Data were collected on growth hormone doses, scoliosis, height SDS and IGF1 levels. IGF1 levels higher than 2 standard deviations classified as high. Height gain calculated from the height SDS before starting GH; including children restarting GH after a period of stopping.

Results: In the non-scoliosis group, mean GH dose was 23 μg/kg per day (S.D. 8). Mean height SDS gain was: −0.30 in the year before GH (baseline); +0.70 after 1 year on 15–25 micrograms/kg/day (n=14); and +0.39 on >25 μg/kg per day (n=12) (both P<0.02). In the scoliosis group, mean GH dose was 20 μg/kg per day (S.D. 6). Mean height SDS gain was: −0.33 at baseline; +0.22 after 1 year on 15–25 μg/kg per day (n=12) (P=0.04), and +0.04 on >25 μg/kg per day (n=2), (P=0.09). After 2 years on GH, the mean height SDS gain in all children: without scoliosis (n=20) was +0.9; and with scoliosis (n=17) was +0.28, (P<0.03). After 5 years, height SDS gain was +1.24 and +1.02, respectively (P=0.62). No significant differences in mean GH dose between the normal IGF1 group (n=12) and high IGF1 group (n=23), 19 μg/kg per day and 16 μg/kg per day, respectively (P=0.47). After 2 years on GH, mean height SDS gain was +1.21 in the normal IGF1 group and +0.4 in the high IGF1 group (P<0.01). After 5 years of treatment, the height SDS gain was +1.15 in normal IGF1 group and +1.03 in high IGF1 group (P=0.7)

Conclusions: Scoliosis and high IGF1 appeared to have minimal effects on height gain in the long term. Height gain on 15–25 μg/kg per day of GH was not inferior to higher doses. Further research to review whether lower GH doses may be used in future, and implications for side effects and cost-effectiveness.