Growth hormone secretion and serum insulin-like growth factor-I concentration in X-linked hypophosphatemic rickets before and after treatment.
The aetiology of growth retardation in children with X-linked hypophosphatemic rickets (HPR) has not been totally defined. We evaluated growth hormone (GH)/insulin-like growth factor-I (IGF-I) changes in relation to linear growth and biochemical parameters in seven children with X-linked hypophosphatemic rickets before and after treatment with 1,25-dihydroxyvitaminD3 and phosphate therapy for a year or more. Moreover, we compared patients' growth data and GH/IGF-I changes with those for 20 age-matched children with normal variant short stature (NVSS)[with normal GH secretion and height standard deviation score (HtSDS) before -2]. Before treatment, all children with HPR secreted normal GH in response to clonidine provocation (> 10 microgram/l) and their IGF-I concentration was significantly lower than those with NVSS. The HtSDS and growth velocity (GV) of children with HPR improved significantly after (-3.05, 8.9 cm/year, respectively) v. before (-3.9 and 4.1 cm/year, respectively) therapy. Their serum IGF-I concentration increased significantly from 76.7 ng/ml before to 99.6 ng/ml after treatment. In summary children with HPR had no abnormality of GH secretion but improvement of their linear growth was associated with significant increase of circulating IGF-I concentration after treatment.
Soliman
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Department of Pediatrics, Royal Hospital, Muscat, Oman.
alSalmi
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D002648:Child; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000209:etiology*; D019382:Human Growth Hormone / Q000097:blood* / Q000627:therapeutic use; D006801:Humans; D007015:Hypophosphatemia, Familial / Q000097:blood* / Q000150:complications / Q000188:drug therapy*; D007223:Infant; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D009850:Oman; D011446:Prospective Studies; D011863:Radioimmunoassay; D018709:Statistics, Nonparametric
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I