The impact of the d3-growth hormone receptor (d3-GHR) polymorphism on the therapeutic effect of growth hormone replacement in children with idiopathic growth hormone deficiency in Poland.

OBJECTIVES: The human growth hormone receptor (GHR) exon 3 deletion (d3) polymorphism has been reported to be associated with the responsiveness to growth hormone (GH) therapy. This study aimed to: (a) assess the frequency of this polymorphism in a group of Polish children with idiopathic growth hormone deficiency (IGHD) and (b) analyze their response to GH therapy.

METHODS: The study group consisted of 67 prepubertal children with IGHD. The control group was composed of 150 Caucasian newborns from whom umbilical cord blood samples were drawn. A genotype analysis was performed using the PCR multiplex technique in search for the existence or deletion of exon 3 of the GHR gene.

RESULTS: In the study group the following genotype distribution was observed: fl/fl-GHR 64.2%; fl/d3-GHR 29.9%; d3/d3-GHR 5.9%. The total percentage of patients with d3-GHR polymorphism was 35.8% and 64.2% patients had a fl/fl-GHR. No significant differences were noted in growth rate SD before introducing therapy and growth rate after one year of recombinant human GH therapy in patients with individual genotypes. In the control group the genotype distribution was: fl/fl-GHR 63.3%; fl/d3-GHR 29.9%; d3/d3-GHR 6.8%.

CONCLUSION: No differences were observed in genotype distribution between the study and the control group. Patients with IGHD did not differ among each other depending on their genotype (fl/fl-GHR or fl/d3-GHR) in terms of growth velocity before introducing therapy or growth rate after one year of recombinant human GH therapy.