Noonan syndrome (NS) is an autosomal dominant disorder that can be difficul
t to diagnose. Growth retardation is a consistent feature, however, and alt
hough children are not typically growth hormone (GH) deficient, a minority
may have suboptimal GH levels. An ongoing multicentre study examining the s
afety and efficacy of GH therapy in NS showed increases in height standard
deviation scores (SDS; p < 0.0001) and height velocity (p < 0.0001) after 1
2 months of GH at pharmacological doses. There was no increase in mean maxi
mal cardiac left ventricular wall thickness during the 12-month treatment p
eriod. Long-term follow-up data covering 3 years of GH therapy showed susta
ined increases in height SDS and height velocity compared with baseline (p
< 0.02). Further large and appropriately controlled studies of high-quality
design are essential to further our understanding of NS and to establish t
he long-term safety and efficacy of GH. Copyright (C) 2000 S. Karger AG, Ba
sel.