21 Hydroxylase deficiency

• Autosomal recessive adrenogenital syndrome
• most common enzyme deficiency (95% of cases)

• deficiency in 21-hydroxylase causes hypocortisolism —> increase in ACTH (no negative feedback) & increase in 17-ketosteroids, testosterone and DHT, decrease in cortisol & aldosterone
  • increase in ACTH —> hyperpigmentation, adrenal hyperplasia
  • increase in testosterone —> precocious puberty in males, ambiguous genetlia in females
  • decrease in cortisol & aldosterone (because of enzyme block) —> Na and H2O loss, low BP, hyperkalemia

http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/adrenal/cah21.gif