Abstract: Abstract： Objective To investigate the possible association of circulating components of GH-IGFs-IGFBPs system with the GHR-exon 3 genotype in idiopathic short stature (ISS) children. Methods Genomic DNA was extracted and isolat⁃ ed from peripheral leukocytes in 108 ISS children. GHR-exon 3 polymorphism was analyzed with multiplex poly- merase chain reactions (PCR) assay. According to the results of genotype, ISS children were divided into GHRfl group and GHRd3 group. The height and weight were recorded in two groups. The body mass index (BMI) and BMI standard deviation score (SDS) were measured. The serum levels of insulin-like growth factor (IGF) -1, IGF-binding protein (IGFBP)-3, IGF-1 SDS and IGFBP3 SDS were calculated. GH stimulation test was used to measure the serum GH peak value. Fifty-five ISS chil⁃ dren were treated with recombine human GH [0.15 IU/(kg·d)] for three months to analyse the association of IGF-1 responseof GH treatment and genotypes. Results There were 63 GHRfl and 45 GHRd3 in 108 ISS children. There were no signifi⁃ cant differences in BMI, IGF-1, IGFBP3, GH peak, IGF-1 SDS and IGFBP3 SDS between two groups (P > 0.05). Multiple stepwise regression analysis showed that age, IGFBP3, lg (BMI) and lg (GH peak) were influencing factors of lgIGF-1 (P < 0.05). In 55 ISS children treated with rhGH, there were 34 cases of GHRd3. The differences of △IGF-1 and △IGF-1 SDS were higher in GHRd3 group than those of GHRfl group (n=21). Conclusion The GH sensitivity may be a risk factor in ISS children, which may not be related with GHR polymorphism.

Key words:  idiopathic short stature , receptors, somatotropin, gene polymorphism, insulin-like growth factor 1, IGF- binding protein 3, body mass index