RESUMO
<p><b>OBJECTIVE</b>To assess the influence of growth hormone receptor (GHR) Ex3 genotype on the short-term response to recombinant human growth hormone (rhGH) therapy in children with idiopathic short stature (ISS).</p><p><b>METHODS</b>Thirty prepubertal children with ISS receiving rhGH treatment [0.116±0.02 IU/(kg/d)] were randomly recruited. The GHR Ex3 locus was genotyped using a PCR multiplex assay. The growth data including growth velocity, height SDS for chronological age (HtSDSCA), height SDS for bone age (HtSDSBA) and predict final height were compared in children with different GHR genotypes 6 months after rhGH treatment.</p><p><b>RESULTS</b>After 6 months of rhGH treatment, the children with ISS carrying d3/d3 alleles showed a significantly higher increment in growth velocity than those carrying fl/fl alleles (6.3±1.6 cm/year vs 3.4±0.5 cm/year; P<0.05).</p><p><b>CONCLUSIONS</b>The polymorphism in GHR Ex3 is associated with the responsiveness to rhGH treatment, showing that the growth velocity in ISS children with d3/d3 genotype is significantly higher than those with fl/fl genotype.</p>