Phenotypic evolution of classic 21‐hydroxylase deficiency

We describe a female patient who was diagnosed and treated at birth for a classic form of salt-losing congenital adrenal hyperplasia. At 17 years of age, against medical advice, she discontinued both mineralocorticoid and glucocorticoid replacement with no resulting clinical symptoms other than the occurrence of amenorrhoea. Steroid metabolites revealed significant abnormalities of the renin-angiotensin-aldosterone axis, as well as of pituitary-adrenal function. Analysis of our patient's DNA showed only one deleterious CYP21 mutation, an intron 2 base pair change activating a cryptic splice site. We speculate that expression of this patient's CYP21 genes may be altered by the effects of ageing or by changes in the steroid milieu.