Common exon 3 polymorphism of the GH receptor (GHR) gene and effect of GH therapy on growth in Korean children with idiopathic short stature (ISS).

OBJECTIVE: A human GH receptor (GHR) gene exon 3 polymorphism (d3-GHR) has been reported to be associated with responsiveness to GH therapy. We assessed the frequencies of this polymorphism in Korean control and idiopathic short stature (ISS) populations, and analysed short-term growth response to GH therapy according to GHR-exon 3 genotypes in Korean children with ISS. DESIGN AND PATIENTS: This was a retrospective study in 158 ISS children. Auxological and endocrine parameters were measured, and the GHR-exon 3 genotype was analysed. Allelic frequencies of GHR-exon 3 genotype were compared between the ISS group and a control group. GH had been administered for 62 patients, 52 of whom remained prepubertal after the first follow-up year. Changes in height velocity (HV) and IGF-1 and IGFBP-3 concentrations following GH therapy were compared in patients with these genotypes.
RESULTS: There was no difference in GHR-exon 3 genotype frequency between ISS and control groups of Koreans. However, the fl/fl genotype was more frequent in Koreans than in Caucasians. ISS children with d3-GHR showed a significantly higher increment in HV (P = 0.002) and a marginally significant increment in IGF-1 concentration (P = 0.064) at the first year of GH therapy.
CONCLUSION: fl-GHR was more frequently detected in a Korean population than in Caucasians. The growth promotion efficacy of GH therapy differed significantly between ISS patients with and without the d3-GHR allele. These findings indicate that the GHR-exon 3 polymorphism can affect the growth promoting efficacy of short-term GH therapy in Korean children with ISS.