Abstract: Objective This study summarizes the clinical characteristics, gene diagnosis and rhGH treatment response of six Noonan syndrome (NS)patients.Methods Six NS patients were collected from May 2009 to August 2015 in Department of Endocrinology, Peking Union Medical College Hospital with clinical characteristics.Five patients were prescribed with rhGH with the initial dose of 0.1IU/kg?dand made the regular follow-up.Ten age/gender matched Turner syndrome (TS) patients and ten growth hormone deficiency (GHD) patients were also collected in the study, aiming to analyze the efficacy differences of rhGH treatment. Results All patients manifested typical features.Five of six patients were treated with rhGH. The annual growth rate of the patients was significantly increased than before (P <0.01).The age-matched NS and TS patients had the similar efficacy of rhGH treatment in every follow-up. However, compared with age/gender matched GHD patients, NS patients revealed less treatment benefit.Adverse events: two NS patients emerged subclinical hypothyroidism during the follow-up. Conclusion NS patients had relatively common symptoms and clinical features, through the precision gene screening is the definite way to confirm. rhGH showed the significant efficacy and safety in the treatment of NS.

Key words: Noonan syndrome, Turner syndrome, growth hormone