CLINICAL STUDY Can exaggerated response to a GH provocative test identify patients with partial GH insensitivity syndrome?

Objectives: In the majority of children with short stature, the etiology is unknown. Mutations of the GH receptor (GHR) have been reported in a few children with apparent idiopathic short stature (ISS). These patients had low IGF-I, IGF-binding protein-3 (IGFBP-3) and GH-binding protein (GHBP), but a normal or exaggerated GH response to provocative stimuli, suggestive of partial GH insensitivity (GHI). We attempted to identify children with partial GHI syndrome, based on their response to GH provocative stimuli and other parameters of the GH–IGF-I axis. Subjects and methods: One hundred and sixty-four pre-pubertal children (97 boys, 67 girls) aged 7.2 (0.5 –16.75) years were studied. All had short stature with height,3rd centile. The weight, bone age (BA) and body mass index (BMI) of the subjects, as well as the parents ’ heights and mid parental height (MPH) were assessed. Basal blood samples were taken for IGF-I, IGFBP-3 and GHBP. All sub-jects underwent a GH provocative test with either clonidine, arginine or insulin. The subjects were divided into three groups: (A) patients with peak GH concentration,18 mIU/l in two different pro-vocative tests (GH deficiency – GHD, n 33); (B) patients with peak GH between 18.2 and 39.8 mIU/l (normal response, n 78); (C) patients with peak GH.40 mIU/l (exaggerated G