ABSTRACT
This is a group of autosomal recessive disorders of adrenal corticosteroid biosynthesis, due to deficiency of one of five enzymes in the cholesterol to cortisol pathway. By far the commonest is 21-hydroxylase deficiency (incidence of 1 in 12 000 live births). This enzyme is also involved in the cholesterol to aldosterone pathway and a deficiency in the zona glomerulosa will lead to aldosterone deficiency and a salt-losing tendency. A less common cause of CAH is 11ß-hydroxylase deficiency which does not usually cause a salt-losing tendency but hypertension may be a prominent feature.
