Non-classic congenital adrenal hyperplasia.

Congenital adrenal hyperplasia results from a defect in the biosynthetic pathway of cortisol and/or aldosterone. Non-classical ( NCAH) forms are characterized by milder enzyme dysfunction and manifests commonly in adolescence or adulthood. The most common form of NCAH is 21 hydroxylase (21-OH) deficiency. Also, a number of NCAH patients with 11 beta hydroxylase (11 beta-OH) deficiency have been reported in some populations. Although some patients with NCAH may be asymptomatic, hirsutism is the most common symptom. It may be clinically indistinguishable from PCOS. Mutations in the CYP21 (CYP21A2) gene which is located on chromosome 6p21.3 along with a pseudogene, CYP21P (CYP21A1P), are responsible for cases of 21- OH deficiency. The ACTH stimulation test is the best screening test for evaluating adrenal gland functions. NCAH due to 21-hydroxylase deficiency is diagnosed when the ACTH-stimulated 17-OHP levels > 30 nmol/ l; this threshold varies depending on the assay. Asymptomatic patients with NCAH do not need glucocorticoid treatment. If the main concern of the patient is infertility, ovulation induction is the treatment of choice. If the patient seeks medical advice because of hirsutism, anti-androgens may be used. NCAH is not characterized by cortisol insufficiency and these patients do not need glucocorticoid replacement before and/or during surgery unless they have been treated chronically with glucocorticoids.