Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder affecting adrenal steroid biosynthesis.For the paediatric endocrinologist,the presentation is at birth manifest as ambiguous genitalia in girls and as salt loss in both sexes.The affected male has normal external genitalia and the salt loss is delayed until the second week of life.Hence,a life threatening salt-losing crisis may occur accounting for the sex imbalance of this disorder in the past.Several countries now screen for CAH at birth for this reason,but that policy does not operate in the UK.Later in infancy and childhood,management is focussed on growth monitoring and provision of steroid replacement to ensure the normal onset of puberty.
The adult and reproductive endocrinologist have the task of continuing compliance with treatment to ensure normal ovarian function and potential fertility in females and in males,the avoidance of the development of testicular masses due to adrenal rests.
The molecular genetics of CAH is well characterised,particularly for the commonest enzyme defect,21-hydroxylase deficiency.The genotype is sufficiently predictive of the severity of CAH as to be helpful in prenatal diagnosis and treatment throughout the lifespan.Indeed,it is now possible to treat CAH antenatally by administration of steroids to the mother and prevent virilisation of the external genitalia in affected females.This is a rare example of prenatal treatment of a major congenital malforamtion.
22 - 24 Mar 2004
British Endocrine Societies