Young adult Prader-Willi (YAP) Syndrome Study: Effects of growth hormone after final height: A clinical care to the optimal dosage of growth hormone in young adults with PWS.

GH improves height velocity, and body composition in PWS children. Preliminary
data also suggest improvement of psychosocial functioning during GH. When
epiphysial fusion is complete and final height is reached, GH-treatment has to
be discontinued. However, preliminary results show that in patients with Prader
Willi syndrome discontinuation of GH results in a decrease of lean body mass,
an increase of body fat percentage and a deterioration of psychosocial
behaviour. We expect the Transitionstudy (dubble blind, placebo controlled
study) to show that young adults with PWS might also benefit from GH-treatment,
with regard to body composition, and psychosocial wellbeing.

Psychiatric disorders are reported in adults with Prader-Willi syndrome. No
longitudinal studies have described the prevalence, natural course and
prevention of psychiatric disorders in adults with PWS. Psychiatric symptoms
and psychiatric disorders occur frequently in persons with PWS, therefore it is
of utmost importance to study this prevalence and course into adulthood in a
longitudinal design. The obtained information of this amendment unites
perfectly with the earlier and future obtained data on behaviour and cognition
in children with PWS, who are part of a unique cohort of 140 Dutch children
with PWS (MEC 205.253/2001/230 amendment (number unknown) approved at June
30th, 2010 and MEC 2007-189 amendment 1, approved September 9th, 2010).

To evaluate the effects of GH, after final height is reached, on weight, body
composition, psychosocial functioning, carbohydrate metabolism and serum
lipids.

To find an optimal dose growth hormone for adults with PWS. We aimed to
stabilize the body composition and psychosocial functioning and psychiatric
functioning.

Before (re)starting GH, patient visits the outpatient clinic for the following
assessments
- Oral glucose tolerance test
- Laboratory test
- weight, Waist-hip ratio
- Blood pressure
- DXA scan

Additional tests during the following years:
- DXA for body composition and bone density [at start, at 6 months, at 12
months and yearly thereafter]
- Nutritional intake during 7 days (via daily intake book) [at 12 mo intervals]
- Laboratory assessments [at start, at 6 months, at 12 months and yearly
thereafter]
- Oral glucose tolerance test (every 5 years)

Treatment with Norditropin 0,33mg/m2/dag. The GH dose will be titrated to serum
IGF-1 levels between +1 SDS and +2 SDS, based on IGF-1 measured after 6 months
GH treatment and a DXA scan.

Burden:
- Filling out questionnaires
- Oral glucose tolerance test (once every 5 years)

Benefit:
The positive effects of GH on bodycomposition and psychosocial behaviour.
The positive effects of GH on psychiatric functioning.

Group relatedness:
applicable for other adolescents and adults with Prader Willi syndrome