Noonan syndrome presenting growth hormone neurosecretory dysfunction.

Noonan syndrome has been diagnosed by the characteristic physical stigmata for more than two decades. Recent studies of growth hormone secretory pattern provide a new category of growth hormone neurosecretory dysfunction to characterize short stature. We describe herein a case of growth hormone neurosecretory dysfunction in a 16-year-old boy with Noonan syndrome. Growth hormone neurosecretory dysfunction was diagnosed primarily based on the low amplitude and small numbers of the spontaneous bursts of growth hormone secretion during 12-hour nocturnal growth hormone sampling. Treatment with synthetic human growth hormone has markedly accelerated the growth velocity for one year and a half. This case notes the wide spectrum of short stature in Noonan syndrome and the effectiveness of treatment with human growth hormone.