Nonclassic 21-hydroxylase deficiency.

The nonclassic form of adrenal hyperplasia (NCAH) has been increasingly recognized in adolescent or adult hyperandrogenic patients. It is now widely accepted that neither the clinical presentation nor the androgen plasma levels can be used for the screening or diagnosis of NCAH in hyperandrogenic women, especially those presenting with a phenotype like that in polycystic ovary syndrome. Therefore, the measurement of a follicular morning level of serum 17-hydroxyprogesterone (17-HP) should be included in the initial investigation of all hyperandrogenic women, including those with premature pubarche. Levels of 17-HP lower than 2 ng/mL (6.0 nmol/L) and greater than 4 ng/mL (12.0 nmol/L) have good predictive negative and positive values, respectively. The adrenocorticotropic hormone test is useful only when the morning follicular unsuppressed 17-HP level falls between 2 and 4 ng/mL (6 to 12 nmol/L). Adrenal insufficiency and adrenal hyperplasia are more theoretical than real complications of NCAH. On the other hand, the polycystic ovary syndrome and infertility are frequently associated with NCAH. For the treatment of hyperandrogenism, the conventional treatment by glucocorticoid therapy is challenged by cyproterone acetate, but it is still indicated when patients wish a pregnancy. It can be questioned whether the low risk of virilized female newborns in untreated women with NCAH justifies prenatal diagnosis and treatment.