clinical features

Last reviewed 08/2021

Females are virilised at birth with clitoral hypertrophy and variable labial fusion of the labia minora. They may be mistaken for male babies with bilateral cryptorchidism and hypospadias. Hirsutism develops in 10% of patients, usually, at adolescence. Post-pubertal amenorrhoea is common.

The condition is less easy to recognise in newly born males and may go undiagnosed until there is an adrenal crisis in the first weeks of life.

There may be hyperpigmentation; in males this may be particularly apparent in the scrotum.

An adrenal crisis is characterised by salt loss and circulatory collapse. It usually occurs in the first few days of life and may be preceded by vomiting and poor weight gain. Cortisol and aldosterone are low or absent. Serum ACTH and 17-hydroxyprogesterone, and urinary pregnanetriol and 17-oxosteroids are elevated.

11-hydroxylase deficiency produces virilisation, salt retention and hypertension. Initial growth may be excessive but the advanced bone age may limit final adult stature.

Males born with 3-beta hydroxysteroid dehydrogenase deficiency fail to develop normal external genitalia due to a lack of testosterone. Females are slightly masculinised from overproduction of DHEA-S.

Life-threatening hypoglycaemia may accompany cortisol deficiency due to omission of steroids or intercurrent illness.