Clinical Significance of Serum IGF-I Level in Short Stature Children / 대한소아내분비학회지

ABSTRACT

PURPOSE: Insulin-like growth factor I(IGF-I) is a polypeptide mitogen and mediates growth effect of growth hormone(GH). The lack of daily variation of IGF-2 allows their measurements to be reliable in screening for growth disorders. The aims of this study are to evaluate the mean levels of IGF-I and also to evaluate whether IGF-I has diagnostic significance as a screening test in short stature children. METHODS: We studied 71 short stature children(Male 43, Female 28)whose test results were normal after GH provocation test(L-dopa and/clonidine). Control group was 13 children with GH deficiency(complete GH deficiency 6 cases, partial GH deficiency 7 cases). Serum GH level was measured with radioimmunoassay(RIA, Diagnostic system laboratories, USA) kit. and serum IGF-I level was measured with RIA kit(Nichols co., USA). RESULTS: 1) Study group included 71 short stature children(male 43, female 28) without GH deficiency and 13 short stature children with GH deficiency(complete GH deficiency 6, partial GH deficiency 7). 2) The height of 43 male children was below 50 percentile except in 3 cases. And 28 female children was below 50 percentile except 1 case. In Tanner standard growth curve. But, 7 male chidren with GH deficiency was below -1SD and 6 female children with GH deficiency was below -2SD. 3) Serum IGF-I level in short stature children without GH deficiency was seen to increase with age and serum IGF-1 level of female was higher than that of male. 4) Serum IGF-I level was correlated with height percentile in study group(male Y=0.017X+0.243, r=0.294, P=0.03, female Y=1.248X+0.716, r=0.384, P=0.01). 5) Serum IGF-I level was -2SD in most GH deficient children. Conclusions: The height was mostly below 50 percentile of the Tanner growth curve in short stature children without GH deficiency. Serum IGF-I level was weakly correlated with the height percentile in both male and female study group. But, serum IGF-I level has limited value of screening test in diagnosis of short stature. However, if serum IGF-I level below -2SD, it could be anti pate the sign for further evaluation of GH deficiency.