Enzyme most commonly deficient in congenital adrenal hyperplasia is

Ans. (a) 21 beta hydroxylaseRef: Bailey and love, 27th ed & Campbell 11th Ed consolidationCongenital adrenal hyperplasia or Adrenogenital syndrome: Features* Salt wasters + virilizers (due to aldosterone deficiency)* Simple virilizers (Aldosterone normal)* Non classified (no virlization, no salt wasting)# Virilization and adrenal insufficiency in children are pathognomonic of congenital adrenal hyperplasia (CAH).# Autosomal recessive disorder# The most frequent defect (95 per cent) is the 21 bhydroxylase deficiency, which has an incidence of 1 in 5000 live births.# Excessive ACTH secretion is caused by the loss of cortisol and this leads to an increase in androgenic cortisol precursors and to CAH.# CAH may present in girls at birth with ambiguous genitalia or as late-onset disease at puberty.# Little Hercules: Hypertension and short stature, caused by the premature epiphyseal plate closure, are common signs.# In female causes Female hermaphrodite# Diagnosed antenatally by 9-11 weeks by chorionic villus sampling# Antenatally mother should be treated with IV Dexamethasone# Affected patients are treated by replacement of Hydrocortisone +- fludrocortisone.# Large hypoplastic adrenals may need to be removed if symptomatic.