Usefulness of an ACTH test in the diagnosis of nonclassical 21-hydroxylase deficiency among children presenting with premature pubarche.

Adrenal steroidogenic function was evaluated in 55 children with typical premature pubarche (PP) to investigate the incidence of late-onset congenital adrenal hyperplasia (LOCAH) due to 21-hydroxylase (21-OH) deficiency and to evaluate the usefulness of routine ACTH testing in these patients. Four patients fulfilled criteria for LOCAH due to 21-OH deficiency. Of these, 3 had elevated baseline 17-OHP levels; in the remainder, basal 17-OHP was within normal limits. Mean basal and stimulated 17-OHP responses in children with PP, excluding those with an enzymatic defect, were very similar to those of controls (2.3 +/- 1.8 vs. 1.6 +/- 0.9 and 10.0 +/- 4.0 vs. 9.5 +/- 3.3 nmol/l, respectively). However, 5 patients had basal 17-OHP values exceeding the upper limit of controls and 8 patients, including 2 of those with elevated baseline levels, showed supranormal poststimulated 17-OHP values. Body mass indices, height standard deviation scores (SDS) and bone age SDS showed no correlation with the basal or incremental rises of any hormone. Four (7%) of our population of patients with typical PP had LOCAH due to 21-OH deficiency. Basal 17-OHP levels were helpful in detecting altered steroidogenesis in 3, thus suggesting that in some PP patients, LOCAH due to this enzymatic defect may remain undiagnosed if ACTH stimulation test is not routinely performed.