Endocrine Abstracts

Background: Prader-Willi syndrome (PWS) is a complex genetic disorder caused by lack of expression of paternally inherited imprinted genes on Chr15q11-q13. rhGH has beneficial effects on growth, body composition and development. Starting age, dose titration and monitoring remain controversial.

Objective: To study retrospectively children who presented in our multidisciplinary PWS clinic and assess response to rhGH treatment in terms of auxology, IGF1 concentration and potential complications.

Method & Patients: In total of 47 patients (male 27, female 20) were followed up; 5/47 were lost to follow-up and 2/47 refused rhGH treatment. 40 patients were treated with rhGH, all had detailed sleep studies before, and six weeks after starting treatment.

Results: Treatment started at a mean age of 2.1±2.6 years (range 0.58–12.8), 45% of patients (n=18) started rhGH before the age of one (0.58–0.97 years). 15% (n=6) had evidence of sleep apnoea, requiring non invasive ventilation before starting rhGH. Mean starting rhGH dose was 0.025 mg/kg/day (0.5 mg/m²/day) increased to 1 mg/m²/day following the second sleep study. At one year, mean dose was 0.7±0.2 mg/m²/day. Pre-treatment mean height was −1.65±1.1 SDS (−4.47 to 0.37 SDS), with a weight of −1.43±1.8 SDS (−5.5 to 3.3) and BMI of −0.46±1.6 SDS (−3 to 4). After one year there was an increase of 1.37SDS in Ht (mean −0.28±0.94, range −2.4 to +2.3), with a mean weight of −0.24±1.8 SDS (range −4.0 to 3.7) and BMI of 0.08±2 SDS (−3.0 to 4.6). No patient had worsening respiratory status and 2/6 patients discontinued ventilatory support. One patient paused treatment during spinal surgery and restarted afterwards. IGF1 was >+2.0 SDS in 60% of patients and the dose of rhGH remained unchanged with repeat yearly IGF1 measurement.

Conclusion: Early treatment with GH results in improved height in the first year with no adverse effect on respiratory function. We recommend dose titration using auxology and IGF1 concentration.