Congenital adrenal hyperplasia is a metabolic disorder related to enzymatic defects in the biosynthesis of cortical steroids. Typically the defects are inherited in an autosomal recessive manner, and within a particular family all inherit the same enzyme deficiency (1).
Two principal effects result from the enzyme deficiency:
- deficient cortisol and/or aldosterone production
- excess precursor steroids
In response, there is increased ACTH secretion from the anterior pituitary producing adrenocortical hyperplasia.
At least eight distinctive clinical syndromes are recognised but the majority of cases are attributed to:
- 21-hydroxylase deficiency (approximately 95%)
- 11-beta-hydroxylase deficiency (approximately 5%)
The deficiency forms of CAH which are associated:
- with male pseudohermaphrodite include 21alpha-hydroxylase and to a lesser extent 11-beta-hydroxylase
- with female pseudohermaphrodite include 17alpha-hydroxylase, 17,20 lyase, 3beta-hydroxysteroid dehydrogenase, and cholesterol 20,22 desmolase;
- while CAH forms which are associated with hypertension include 17alpha-hydroxylase and 11beta-hydroxylase deficiency (2)
- Ogilvy-Stuart A.Endocrinology of the neonate, BJHM 1995;54(5): 207-11.
- Honour JW. Diagnosis of diseases of steroid hormone production, metabolism and action. J Clin Res Pediatr Endocrinol 2009;1(5):209-226