Abstract
BackgroundNoonan syndrome (NS) is an autosomal dominant disorder characterized by specific features including short stature, distinctive facial dysmorphic features, congenital heart defects, hypertrophic cardiomyopathy, skeletal anomalies and webbing of the neck. Molecular screening has shown that the majority of individuals with NS have a mutation in the PTPN11 gene. Noonan syndrome children may show an impaired growth hormone (GH)/insulin-like growth factor axis. Moreover, recombinant human GH (rhGH) has been shown to improve growth rate in patients with NS, although data are still limited.MethodsIn the present study, we assessed growth response following GH therapy (0.25 mg/Kg/week) in 5 (2 M and 3 F) GH-deficient NS patients (NSGHD, mean age 8.5 years) and in 5 (2 M and 3 F) idiopathic GH deficient (IGHD, mean age 8.6 years) patients. We also evaluated the safety of rhGH therapy in NS patients with GHD.ResultsAt the beginning of GH treatment, height and growth rate were statistically lower in NSGHD children than in IGHD ones. During the first three years of rhGH therapy, NSGHD patients showed a slight improvement in height (from −2.71 SDS to −2.44 SDS) and growth rate (from −2.42 SDS to −0.23 SDS), although the values were always significantly lower than in IGHD children. After five years of rhGH treatment, height gain was higher in IGHD children (mean 28.3 cm) than in NSGHD patients (mean 23.6 cm).During the first five years of rhGH therapy, regular cardiological and haematological check-ups were performed, leading to the conclusion that rhGH therapy was safe.ConclusionsIn conclusion, pre-pubertal NS children with GHD slightly increased their height and growth rate during the first years of GH therapy, although the response to rhGH treatment was significantly lower than IGHD children. Furthermore, the therapy appeared to be safe since no severe adverse effects were reported, at least during the first five years. However, a close follow-up of these patients is mandatory, especially to monitor cardiac function.
Highlights
Noonan syndrome (NS) is a disorder first reported by the paediatric cardiologist Jaqueline Noonan in 1963 [1] and described in detail a few years later by the same author [2] and by other groups [3]
Children affected by NS and growth hormone deficient (GHD) and children with only GHD had comparable chronological age and body mass index (BMI) at the time of endocrinological evaluation
They differed in height and growth rate, which were statistically lower in Noonan syndrome growth hormone deficiency (NSGHD) children than in idiopathic GH deficient (IGHD) ones
Summary
Noonan syndrome (NS) is a disorder first reported by the paediatric cardiologist Jaqueline Noonan in 1963 [1] and described in detail a few years later by the same author [2] and by other groups [3] It is an autosomal dominant disorder, affecting 1 in 1,000–2,500 live births with no sex predominance, and is the most common syndromal cause of congenital heart disease, except for Down’s syndrome. Molecular screening has shown that the majority of individuals with a diagnosis of NS have a mutation in the PTPN11 gene (30–60 %) that encodes for the protein tyrosine phosphatase SHP2 [8]. Noonan syndrome (NS) is an autosomal dominant disorder characterized by specific features including short stature, distinctive facial dysmorphic features, congenital heart defects, hypertrophic cardiomyopathy, skeletal anomalies and webbing of the neck. Recombinant human GH (rhGH) has been shown to improve growth rate in patients with NS, data are still limited
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