Subnormal serum insulin-like growth factor-I levels in young adults with childhood-onset nonacquired growth hormone (GH) deficiency who recover normal gh secretion may indicate less severe but persistent pituitary failure.
BACKGROUND
The unexpected observation of a normal GH peak in 22% of young adults with childhood-onset GH deficiency (GHD) and ectopic neurohypophysis has raised questions about the criteria defining GHD in young adults and whether patients with subsequent increases in GH secretion nonetheless have a subtle form of GHD.


OBJECTIVE
Our objective was to determine the characteristics of patients with childhood-onset nonacquired GHD who recover normal peak GH secretion when adult height has been achieved.


METHODS
We conducted a university hospital-based observational follow-up study.


METHODS
Sixty-two patients with ectopic neurohypophysis (n = 24), isolated hypoplastic anterior pituitary (n = 14), or normal hypothalamic pituitary area (n = 24) on magnetic resonance imaging (MRI) at the time of GHD diagnosis underwent reevaluation of the GH-IGF-I axis at a mean age of 16.8 +/- 1.6 yr.


METHODS
Outcome measures included clinical and MRI findings and serum IGF-I and peak GH levels.


RESULTS
On retesting, peak GH exceeded 10 microg/liter in 31 patients (50%): six (20%) patients with ectopic neurohypophysis, 10 (32%) patients with initially isolated hypoplastic anterior pituitary, and 15 (48%) patients with normal MRI findings. Among these patients, serum IGF-I levels were significantly lower in patients with ectopic neurohypophysis than in those without structural abnormalities of the hypothalamic pituitary axis (n = 25), but patients without structural abnormalities also had significantly lower serum IGF-I levels than control subjects, after controlling for age, sex, and body mass index (mean serum IGF-I levels of 374 +/- 83 vs. 446 +/- 108 microg/liter; beta-coefficient = -72; P = 0.003).


CONCLUSIONS
The severity of the disease seems to have decreased over time in these patients, who may nonetheless present persistent pituitary failure. The natural history and clinical implications of these findings remain to be clarified. The possibility of a deterioration in the secretion of GH and other pituitary hormones later in life in a subset of these patients warrants the careful long-term follow-up of this population.
Gelwane
Georges
G
Pediatric Endocrinology Department, Centre de Référence Maladies Endocriniennes de la Croissance and Institut National de la Santé et de la Recherche Médicale (INSERM) Unit 690, Paris, France.
Garel
Catherine
C
Chevenne
Didier
D
Armoogum
Priscilla
P
Simon
Dominique
D
Czernichow
Paul
P
Léger
Juliane
J
D000293:Adolescent; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency* / Q000378:metabolism; D006801:Humans; D007018:Hypopituitarism / Q000378:metabolism* / Q000473:pathology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism / Q000473:pathology; D020127:Recovery of Function; D012720:Severity of Illness Index
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I