ACTIVE HYPOTHALAMIC-PITUITARY-GONADAL AXIS IN AN INFANT WITH X-LINKEDADRENAL HYPOPLASIA CONGENITA

To evaluate the hypothalamic-pituitary-gonadal axis in an infant with adrenal hypoplasia congenita, we measured the serum levels of testoste rone and performed a luteinizing hormone-releasing hormone stimulation test, The diagnosis was made because of the presence of a mutation, A 300V, in the DAX-1 gene, The results demonstrated an active hypothalam ic-pituitary-gonadal axis, with adult-level testosterone of 266 ng/dl on day 0, and maintenance of testosterone concentration in the 100 to 250 ng/dl range for 140 days as expected. The luteinizing hormone-rele asing hormone test was compatible with an active pituitary gland with a luteinizing hormone peak of 13.1 IU/L and a follicle-stimulating hor mone of 5.0 IU/L. We conclude that the DAX-1 mutation does allow a nor mal reproductive axis at birth. We speculate that sometime between inf ancy and puberty this mutation in the DAX-1 gene leads to an inability to activate the reproductive axis from its childhood suppression; thu s puberty will not develop in this infant.