Congenital Adrenal Hyperplasia Basics : Explained with Mnemonics

Adrenal cortex synthesize steroids.

Mnemonic: GFR – Salt, Sugar, Sex

  • Zona gomerulosa: Salt (Aldosterone)
  • Zona fasciculata: Sugar (Cortisol)
  • Zona reticulosa: Sex (Testosterone)

Congenital adrenal hyperplasia (CAH)

cah enzymesDeficiency of 3 different enzymes can cause Congenital Adrenal Hyperplasia.

Mnemonic: Remember the mnemonic GFR, first layer of cortex synthesizes aldosterone and the last layer synthesizes sex steroids. So, the numberals in enzyme can be assumed to represent following:

  • 1st digit: Blood pressure
  • 2nd digit: Testosterone

The “1” looks like an up arrow, hence, it signifies “increase“.

All the 3 conditions are associated with the hypertrophy of adrenals due to high levels of ACTH (lack of suppression). In all 3 conditions corticosteroid is decreased. The most common one is due to 21 hydroxylase deficiency.

1. 11 hydroxylase deficiency:

  • 1 – Increased blood pressure (hypertension)
  • 1 – Increased testosterone (virilization in females)

2. 21 hydroxylase deficiency:

  • 2 – Decreased blood pressure (hypotension)
  • 1 – Increased testosterone (virilization in females)

3. 17 hydroxylase deficiency:

  • 1 – Increased blood pressure (hypertension)
  • 7 – No increase in testosterone

adrenal steroidogenesis

  1. Adrenal steroidogenesis is regulated by ACTH from anterior pituitary gland.
  2. Circulating level of plasma cortisol is a key player in the hypothalamic-pituitary-adrenal feedback system and exerts a negative feedback effect on the secretion of ACTH .
  3. ACTH secretion increases due to decrease in cortisol secretion as in CAH (loss of negative-feedback on ACTH) resulting in:
    • Overstimulation of the adrenals – hyperplasia
    • Stimulation of excessive synthesis of the adrenal products of those pathways unimpaired by an enzyme deficiency and causes an accumulation of precursor molecules in pathways blocked by an enzyme deficiency.

3 B-HSD is involved in synthesis of all 3 steroids involved in salt, sugar and sex.

Mnemonic: 3 involves all 3

  • Hence, deficiency of 3 B-HSD leads to decrease in all 3 steroids.

21 OH and 11 OH are involved in synthesis of salt and sugar only.

  • Hence, deficiency of 21 OH and 11 OH enzymes lead to increase in sex steroids.
  • In 11 OH deficiency, hypertension occurs due to accumulation of Deoxycorticosterone (DOC) which has mineralocorticoid activity.

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