Short stature with normal growth hormone stimulation testing: lack of evidence for partial growth hormone deficiency or insensitivity

Abstract

OBJECTIVES: To test the hypothesis that children with short stature and peak stimulated GH (pGH) of 7-10 microg/l have partial GH deficiency and to test the hypothesis that short children with normal pGH but low IGF-I levels have partial GH deficiency or partial GH insensitivity. DESIGN AND PATIENTS: Retrospective analysis of the clinical and biochemical profiles of 76 children who underwent an evaluation for short stature (height < 5th percentile) that included two, sex steroid-primed GH stimulation tests. RESULTS: Patients with pGH < 7 microg/l (n = 14) differed significantly from those with pGH > 7 microg/l (n = 62), having greater midparental height (MPH) SDS, a greater disparity between height SDS and MPH SDS, and lower IGF-I SDS. Patients with pGH of 7-10 microg/l (n = 12) did not have characteristics intermediate between those with pGH < 7 microg/l and those with pGH > or = 10 microg/l, but instead resembled those with pGH > or = 10 microg/l. Patients with pGH > or = 7 microg/l, but low IGF-I (< -2 SDS) (n = 5), did not show characteristics intermediate between those with pGH < 7 microg/l and those with pGH > or = 7 microg/l and normal IGF-I. CONCLUSIONS: These data do not support either the hypothesis that children with pGH of 7-10 microg/l have partial GH deficiency or the hypothesis that children with normal pGH but subnormal IGF-I levels have partial GH deficiency or insensitivity.