[Congenital adrenal hyperplasia: clinical aspects and neonatal screening]

Congenital adrenal hyperplasia (CAH) is a disorder of adrenal steroid synthesis. In 95% of CAH cases, it is caused by 21-hydroxylase deficiency, leading to cortisol deficiency and (in most cases) aldosterone deficiency. The compensatory increase in ACTH secretion by the pituitary gland leads to stimulation of the adrenal glands and, consequently, overproduction of androgens. The classic form is well known due to the congenital virilisation seen in affected girls. However, the cortisol and aldosterone deficiency is at least equally important in both sexes as it can cause an Addisonian crisis within the first weeks of life. For these reasons, a neonatal CAH screening program has been introduced in the Netherlands. Screening results in earlier detection and treatment. The prevalence of the classic form of the disease is 1:12.000 in the Netherlands. Non-classic 21-hydroxylase deficiency is more frequent, presenting with signs of androgen excess from childhood through to adulthood. Treatment of CAH consists of hormonal replacement and surgical correction in case of congenital virilisation in girls. Long-term treatment results, including height at adulthood, have improved over the last decades. Nevertheless, fertility problems can occur in both sexes.