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.
Zevenhuijzen
H
H
Section of Child Life and Health, Department of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, UK.
Kelnar
C J H
CJ
Crofton
P M
PM
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