Calcium-phosphate metabolism and bone markers in two patients with Noonan's syndrome treated with growth hormone
Praticò, G.; Palano, G.M.; Lo Presti, D.; Parisi, G.; Caruso-Nicoletti, M.
Minerva Pediatrica 55(6): 593-598
2003
ISSN/ISBN: 0026-4946 PMID: 14676730 Document Number: 554700
Aim: To evaluate the possible effects of recombinant growth hormone (rhGH) therapy on mineral homeostasis and bone turnover, the authors studied calcium-phosphate metabolism parameters, including some bone markers, in two prepubertal subjects with Noonan's syndrome (NS) [Italy]. Methods: Two prebubertal males suffering from NS, short stature (-3.9 and -5.4 SDS, respectively) and low growth velocity (3.9 and 3.3 cm/year), were treated with rhGH (0.85 U/kg/week) for one year. Serum levels of total calcium (Ca), inorganic phosphate (P), magnesium (Mg), parathyroid hormone (PTH), calcitonin (CT), 25 OH vitamin D, 1.25(OH)2D, osteocalcin (BGP), type I procollagen carboxy-terminal propeptide (-PICP) and its telopeptide (ICTP) were measured. Results: The baseline values were in the normal range; during the treatment no remarkable difference in the values of every one parameters was detected in the two patients studied. In one of them, who responded to GH treatment with significantly improved growth velocity, serum levels of the BGP increased during the first semester, and then progressively declined; conversely, serum levels of the ICTP remained stable during the first six months of GH-therapy, whereas increased in the following six months. Conclusion: The results suggest that in Noonan's syndrome patients responding to GH-therapy, a stimulation of bone turnover, with ensuing increase of height velocity, takes place, at least during the first year of GH-therapy. The authors underline the necessity of confirming their results on a larger group of patients with Noonan's syndrome.