Congenital Adrenal Hyperplasia (CAH) refers to a group of disorders that result from the impaired ability of the adrenal glands to produce vital steroid hormones (corticosteroids), two of which, glucocorticoids and mineralocorticoids, are normally active in the body. Low blood levels of the hormonecortisol charge the pituitary gland to produce abnormally high amounts of ACTH (adrenocorticotrophic hormone) which, in turn, stimulates the adrenal cortex to produce androgens or male steroid hormones. Fundamentally, CAH is due to genetic defects (mutations) in the genes controlling the manufacture of the enzymes necessary to produce the hormones of the adrenal cortex.
The various forms of CAH represent enzyme deficiencies at different stages of the production of the steroid hormones. These include 20, 22-Desmolase, 3-Beta Hydroxy-Steroid Dehydrogenase (HSD) Deficiency, 17-Hydroxylase/17, 20-Desmolase Deficiency, 21-Hydroxylase Deficiency, 11-Beta Hydroxylase Deficiency. Almost 95% of cases of CAH are the result of 21-hydroxylase deficiency. The overproduction of male steroid hormones (androgens) at the same time as cortisol and aldosterone are underproduced characterizes the difference between Addison?s disease and CAH.
One rare form of CAH can result from the overgrowth of fatty-like cells in the adrenal glands (congenital lipoid adrenal hyperplasia). This disorder can be causes by20-22 Desmolase Deficiency or by a deficiency of steroid acute regulatory protein (StAR).
