SAT-226 Effects of growth hormone treatment in children with Noonan

Abstract Disclosure: L. Hanna Moura da Silva Gattas Graciolli: None. M.F. Fernandes Martins: None. L.V. Silva Andrade: None. T. Del Monaco Rezende Oliveira Cardoso: None. A. Bocato: None. J. Almeida de Souza: None. M. Rodrigues Paiva: None. M. Costa Tamega: None. J. Moreira Cassemiro: None. T. Souza Buçard: None. O. Naves de Andrade: None. J.S. Rodrigues: None. INTRODUCTION Noonan Syndrome (NS) is an autosomal dominant genetic condition caused by mutations in the RAS/MAPK signaling pathway, the primary mechanism associated with its pathogenesis. It has a homogeneous distribution between sexes and affects individuals of all ethnicities. Its clinical manifestations include short stature, pectus carinatum, congenital heart defects (such as hypertrophic cardiomyopathy and pulmonary valve stenosis), facial dysmorphism, short neck, scoliosis, coagulation factor deficiencies, and cryptorchidism in boys. Short stature, one of the most frequent findings, has a multifactorial etiology, attributed to growth hormone (GH) deficiency or resistance, neurosecretory dysfunction, and reduced levels of insulin-like growth factor 1 (IGF-I). Recent studies suggest that recombinant growth hormone (RhGH) therapy provides significant benefits, increasing growth velocity and improving various clinical parameters. Therefore, it is necessary to assess the effects of hormone treatment in children with NS, exploring its impact on clinical and metabolic outcomes. METHODOLOGY: A systematic review was conducted using the PubMed database, selecting controlled clinical trials, cohort studies, and randomized studies published within the past 5 to 20 years. After applying eligibility criteria and screening the articles, the final sample included four original studies. RESULTS Noordam et al. (2001), in Acta Paediatrica, analyzed the effects of GH over four years, showing a significant increase in growth velocity and patient height without adverse impacts on cardiac function. In another study published in Hormone Research, the same authors investigated the influence of treatment on left ventricular dimensions, concluding that GH therapy did not negatively alter cardiac structure, supporting its cardiovascular safety. More recent studies reinforce these findings. Ozono et al. (2018) compared two doses of somatropin in Japanese patients over two years. Both groups showed significant growth, with the higher dose yielding a better response without relevant adverse events. Similarly, Horikawa et al. (2020) evaluated GH efficacy and safety over four years, confirming greater effectiveness of the higher dose and good treatment tolerability. CONCLUSION The analyzed studies demonstrated the efficacy and safety of GH treatment in children with NS, promoting increased height and growth velocity regardless of ethnicity. No negative impacts on cardiac function were observed, and the treatment’s effects on left ventricular dimensions reinforce its cardiovascular safety. Additionally, higher GH doses proved more effective without significant adverse events. Thus, GH therapy provides significant and safe benefits for children with NS, representing a valid therapeutic approach to enhance growth and quality of life. Presentation: Saturday, July 12, 2025