Endocrine Abstracts

Background: In XY disorders of sex development, a single measurement of serum Anti-Mullerian hormone (AMH) may replace the hCG stimulation test.

Aim: To assess the level of concordance between serum AMH and hCG stimulated testosterone concentrations.

Methods: About 284 children (M:F,154:130) with a median age of 8 years (10th, 90th centiles, 0.25,14) were used to establish a normal reference range for AMH. Clinical data were reviewed on 37 boys with XY undermasculinisation who had an hCG stimulation test (3-day or 3-week) and an AMH measurement.

Results: In the reference group, the 10th centile AMH for boys below the age of 8 years was approximately 250 pmol/l and the 90th centile for girls was 20 pmol/l. In those clinical cases where serum testosterone concentrations were available at D1, D4 and D22 of the 3 weeks-hCG test, 5 cases showed an adequate response (testosterone concentration greater than 5 nmol/l) by D4 and 5 cases showed an adequate response by D22. A low D22 testosterone concentration had a 100% negative predictive value for AMH, whereas a low AMH had a 50% negative predictive value for the D22 testosterone concentration. An AMH of greater than 250 pmol/l had a 100% positive predictive value for testosterone of greater than 5 nmol/l at D22. However, at D4, 67% cases with an AMH of greater than 250 pmol/l had a testosterone greater than 5 nmol/l.

Conclusion: The value of a single AMH measurement for predicting Leydig cell function varies depending on the extent of hCG stimulation. A poor testosterone response on prolonged hCG stimulation remains the optimal test for the assessment of overall testes function.