Congenital Adrenal Hyperplasia

Question 1

What is the inheritance pattern of Congenital Adrenal Hyperplasia (CAH)?

Answer 1

autosomal recessive

Question 2

What enzyme deficiencies can cause CAH?

Answer 2

21-hydroxylase deficiency (90%)
11-beta hydroxylase deficiency (5%)
17-hydroxylase deficiency (very rare)

these enzymes are important for making steroids such as aldosterone etc

Question 3

How does CAH cause virulisation of female infants?

Answer 3

• low cortisol levels
  => anterior pituitary secretes high levels of ACTH
• ACTH stimulates production of adrenal androgens
  => virulisation

Question 4

What test is used to confirm the diagnosis?

Answer 4

ACTH stimulation testing (short synacthen test)

Question 5

Features of 21-hydroxylase deficiency

Answer 5

• virilisation of female genitalia
• early puberty in males
• 60-70% = salt-losing crisis at 1-3 wks of age

Question 6

Features of 11-beta hydroxylase deficiency

Answer 6

• virilisation of female genitalia
• early puberty in males
• hypertension
• hypokalaemia

Question 7

Features of 17-hydroxylase deficiency

Answer 7

• NON-virilising in females
• inter-sex in boys
• hypertension