Growth hormone therapy in Noonan syndrome: growth response and characteristics.

Growth hormone treatment in Noonan syndrome increases growth velocity significantly during the first 2 years of treatment and, to some extent, until puberty. This increase is more pronounced if treatment is started at an early age. Treatment before the age of 5 years is not recommended due to an increased risk of malignancies. In contrast to other growth hormone-treated patients, a slight but significant further increase in height gain can be expected during pubertal growth (at least in boys). Final height improvement varies between 1 and 2 SDS in different studies. Cardiac function does not seem to be impaired during treatment. No significant adverse events have been reported.