Diagnostic utility of a low-dose gonadotropin-releasing hormone test in the context of puberty disorders.
OBJECTIVE
The 10-microg gonadotropin-releasing hormone (GnRH) test assesses pituitary gonadotroph responsiveness, whereas the 100-microg dose assesses maximal secretory capacity. Our aims were to establish normative data for the low-dose test in children and to evaluate the test in diagnosing common pubertal disorders.


METHODS
We retrospectively classified 107 children who underwent 10-microg GnRH tests into normal prepubertal (20 boys, 10 girls), normal early pubertal (10 boys, 16 girls), constitutional delay of puberty (CDP, 13 prepubertal boys >12 years), hypogonadotropic hypogonadism (HH, 5 prepubertal boys >12 years), central precocious puberty (CPP, 19 girls) or premature thelarche/variant (13 girls).


RESULTS
Peak LH response was higher in prepubertal boys >12 years compared with younger boys (p < 0.01) but showed no further change in early puberty. CDP boys had LH responses similar to prepubertal boys >12 years. HH boys showed an absent LH response which diagnosed HH with 100% sensitivity and 96% specificity. Thelarche girls had LH:FSH peak ratios lower than normal prepubertal (p = 0.001), pubertal (p < 0.05) or CPP (p = 0.001) girls.


CONCLUSIONS
We have established normative values for the low-dose GnRH test in children. The test successfully differentiated HH from CDP in boys, and contributed to the differential diagnosis of CPP and premature thelarche in girls.
Section of Child Life and Health, Department of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, UK.
H
H
Zevenhuijzen
C J H
CJ
Kelnar
P M
PM
Crofton
D000293:Adolescent; D041923:Adolescent Development; D001940:Breast / Q000254:growth & development*; D002648:Child; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D007006:Hypogonadism / Q000175:diagnosis*; D008297:Male; D011628:Puberty, Delayed / Q000175:diagnosis*; D011629:Puberty, Precocious / Q000175:diagnosis*; D012189:Retrospective Studies
D007987:Gonadotropin-Releasing Hormone