Context: Noonan syndrome (NS) is characterized by short stature and elevated risk of lymphedema. The mechanism underlying lymphedema may be mediated by vascular endothelial growth factors (VEGFs). Objective: To assess the effect of growth hormone (GH) treatment on plasma insulin-like growth factor (IGF)-1, VEGF-A and VEGF-C levels in patients with NS as compared to short GH-sufficient children. Design: Retrospective, comparative. Setting: Endocrinology department of a tertiary pediatric medical center. Patients and methods: Plasma IGF-1, VEGF-A and VEGF-C levels were measured before and during GH treatment in 6 patients with NS and 18 age-matched short subjects (Turner, idiopathic short stature and small for gestational age). Main outcome measures: Changes in plasma VEGF and IGF-1 levels. Results: Baseline IGF-1 SDS levels were slightly lower in NS patients compared with controls; IGF-1 response to GH therapy was markedly lower in NS patients compared with controls (p = 0.017). Mean baseline VEGF-A levels were similar in NS patients and controls whilst mean baseline VEGF-C levels were significantly lower in the NS group as compared with controls (p = 0.022). Plasma VEGF-A and VEGF-C levels did not significantly change during GH treatment in the study cohort. No correlation was found between VEGF-C levels and levels of IGF-1, VEGF-A and auxological parameters, either before or during GH administration. Conclusion: Children with NS have a distinct growth factor profile including low basal VEGF-C and flattened IGF-1 response to GH. Further studies are needed to confirm our findings and to elucidate the interaction between VEGF-C levels and lymphedema.
- Growth Hormone (GH)
- Insulin-like growth factor-1 (IGF-1)
- Noonan Syndrome
- Vascular Endothelial Growth Factor (VEGF)