Objective:To analyze the clinical manifestations, genetic features and therapeutic efficacy of patients with Noonan syndrome (NS). Methods:The clinical data of 12 NS children treated in Fuzhou Children’ Hospital of Fujian Medical University from September 2015 to April 2021 were analyzed. Among them, 7 patients with height lower than two standard deviations of the mean (or below the third percentile) were treated with recombinant human growth hormone (rhGH), and were followed up every 3?months.Results:The clinical characteristics were as following: facial anomalies (n=12), short stature (n=11), congenital heart diseases (n=5), facial freckles (n=4), coffee spots on the skin (n=3), intelligence disability (n=3),cryptorchidism (n=3), feeding difficulties (n=2), scoliosis (n=2), pectus carinatum (n=2), pectus excavatum (n=1), rib dysplasia companied with short finger (n=1), hyperopia (n=1), myopia (n=1) and early puberty (n=1). ThePTPN11 mutation was detected in 10 cases, RIT1 mutation was detected in 1 case, and RAF1 mutation was detected in 1 case. In 7 patients treated with rhGH, the mean height velocity increased from (2.8±1.0)?cm/year before treatment to (8.3±1.6)?cm/year after treatment for (1.5±0.8)?years (P<0.01); the height velocity was the fastest during 3 to 6?months of treatment, and then gradually went slower. The serum levels of insulin-like growth factor 1 (IGF-1) remained within the normal range.Conclusions:The clinical manifestations of NS are diverse, and the disease can be diagnosed through genetic testing. For NS patients with short stature, rhGH treatment can increase the height velocity and no obvious adverse reactions were found.