The exon3-deleted growth hormone receptor gene polymorphism (d3-GHR) is associated with insulin and spontaneous growth in short SGA children (NESGAS)

Objective The effect of a common polymorphism in the Growth Hormone (GH) receptor (d3-GHR) gene on growth, metabolism and body composition was examined in short children born small for gestational age (SGA) on GH treatment. Design In 96 prepubertal, short SGA children treated with high-dose GH (67 μg/kg/day) in the NESGAS study, insulin sensitivity (IS), insulin secretion and disposition index (DI) were determined during the first year of treatment. Body composition was analysed by DXA. The d3-GHR locus was determined by simple multiplex PCR. Results At baseline, children in the d3-GHR group (d3/fl (n = 37), d3/d3 (n = 7)) had significantly lower IS (median (25–75 percentile)) (223.3% (154.4–304.8)) vs. (269.7% (185.1–356.7)) (p = 0.03) and higher concentrations of glucose (mean (SD)) (4.4 mmol/L (0.6) vs. 4.2 mmol/L (0.7)) (p = 0.03), C-peptide (232.1 pmol/L (168.8–304.1) vs. 185.1 pmol/L (137.7–253.9)) (p = 0.04) and insulin (19.2 pmol/L (11.8–32.2)) vs. (13.7 pmol/L (9.3–20.8)) (p = 0.04) compared to children homozygous for the full length allele (fl/fl-GHR (n = 52)). There were no differences in DI or insulin secretion. Postnatal, spontaneous growth was significantly greater in the d3-GHR group compared to the fl/fl-GHR group (p = 0.02). There were no significant differences in growth response, body composition or metabolism after one year of GH therapy. Conclusion Short SGA children carrying the d3-GHR polymorphism had increased spontaneous growth, lower IS and a compensatory increase in glucose, C-peptide and insulin before GH therapy compared to children homozygous for the full-length allele.