Congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive condition characterized by an insufficient production of cortisol and mineraloactive hormones with a consequent hyperstimulation of hypothalamo-pituitary-adrenal feedback and an increase of androgens. Although the lack of different enzymes in adrenal steroidogenesis can be responsible for different forms of the disease, the deficiency of 21-hydroxylase is the more frequent defect. It is caused by mutations in CYP21 gene located on the short arm of chromosome 6 and it causes a heterogeneous phenotype characterized by a classical form (genitalia virilization in female, early onset acute adrenal insufficiency with salt wasting, precocious pseudopuberty, signs of hyperandrogenism), or by a simple virilizing form (presence of signs of hyperandrogenism without salt-loosing crises) or by a non-classic form evidenced only by mild to moderate signs of hyperandrogenism. The diagnosis can be made by 17-hydroxyprogesterone measurement in basal and after ACTH stimulation test. Glucocorticoid and mineraloactive therapy have been proved to reduce the risk of adrenal crisis reducing the levels of androgens and controlling the symptoms of the disease.