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

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.