[Calcium-phosphate metabolism and bone markers in two patients with Noonan's syndrome treated with growth hormone].
OBJECTIVE
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 2 prepubertal subjects with Noonan's syndrome (NS).


METHODS
Two prepubertal 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 1 year. Serum levels of total calcium (Ca), inorganic phosphate (P), magnesium (Mg), parathyroid hormone (PTH), calcitonin (CT), 25OH vitamin D, 1.25(OH)(2)D, 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 2 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 6 months of GH-therapy, whereas increased in the following 6 months.


CONCLUSIONS
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.
Praticò
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G
Dipartimento di Pediatria, Università degli Studi di Catania, Catania, Italy.
Palano
G M
GM
Lo Presti
D
D
Parisi
G
G
Caruso-Nicoletti
M
M
D000293:Adolescent; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D009634:Noonan Syndrome / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*
D015415:Biomarkers; D010758:Phosphorus; D013006:Growth Hormone; D002118:Calcium