Effect of Human Growth Hormone (hGH) Treatment on Growth Rate and Obesity in Prader-Willi Syndrome

Abstract

Prader-Willi syndrome (PWS) is characterized by short stature, hypogonadism and marked obesity. Because of the effects of GH, it is anticipated to improve the short stature and obesity of PWS with human GH (hGH) treatment. Accordingly we treated two patients with PWS, aged 6 years 1 month and 6 years 4 months, with the dose of 0.5 U/kg/week of hGH. Height of both patients was below -2SD for normal Japanese standard. Peak GH values to provocation tests were over 10ng/mL in case 1, but below 5.1ng/mL in case 2. Growth rate significantly increased with GH treatment as follows: Case 1: Pretreatment growth rate 5.6cm/year, first year 10.6cm/year, second year 7.5cm/year, Case 2: pretreatment growth rate 5.3cm/year, first year 8.3cm/year, second year 6.5cm/year, third year 6.8cm/year, fourth year 7.4cm/year and fifth year 7.7cm/year. Obesity index and body-mass index (BMI) of both cases increased steadily even with GH treatment and these increments were similar to those of other untreated PWS children. From these results it is concluded that GH treatment is effective in accelerating the growth rate in short PWS children. However, this dose not necessarily reduce the obesity index and BMI in PWS. Therefore, it is indicated that another treatment regimen in addition to GH is necessary for improving the obesity and shortness.