Measurement of amino-terminal propeptide of C-type natriuretic peptide in patients with idiopathic short stature or isolated growth hormone deficiency.

Objective: To explore the value of amino-terminal propeptide of C-type natriuretic peptide (NTproCNP) in evaluating the effectiveness of therapy with recombinant human growth hormone (rhGH) in patients with idiopathic short stature (ISS) and isolated growth hormone deficiency (IGHD). Methods: Forty-eight prepubertal children (IGHD=25, ISS=23) treated for at least 1 year with rhGH were included. Insulin growth factor-1 (IGF-I) and NTproCNP serum levels were measured before starting treatment and again 6 months later. Twelve months after starting treatment, all patients were assessed and annual growth velocity (GV), height standard deviation score (HTSDS), and gain HTSDS (Delta HTSDS) were recorded. Results: In the GHD group, positive relationships between GV and change of IGF-I-SDS (Delta IGF-I-SDS), GV and change of NTproCNP concentrations (Delta NTproCNP) were found. GH peak value was also positively associated with IGF-I-SDS and NTproCNP before therapy and Delta IGF-I-SDS and Delta NTproCNP were positively associated. In the ISS group, GV was associated with only Delta NTproCNP. Conclusions: NTproCNP is a novel biomarker of growth as levels increase during growth-promoting treatment. Furthermore, IGF-I is also valuable in evaluating the efficacy of rhGH therapy in short stature patients.