Which enzyme deficiency is most commonly responsible for presence of long clitoris and fused vagina?

Ans. is 'a' i.e., 21 hydroxylase o Features of long clitoris and fused vagina are suggestive of adrenogenital syndrome/ congenital adrenal hyperplasia (CAH). 21 hydroxylase deficiency is responsible for 95% cases of CAH.Congenital adrenal hyperplasiao It is an autosomal recessive disorder. It is due to inborn error of adrenal steroid metabolism, commonly due to 21 - hydroxylase (95%) and rarely due to 11-hydroxylase or 3p hydroxy steroid dehydrogenase deficiency.Clinical presentationo Ambiguity of sex at birth - Cases of ambiguity of sex detected at birth are due to adrenogenital syndrome unless proved otherwise.Hirsutism and amenorrhea may be the presenting features around puberty in milder form.Diagnosis at birtho The suspected anatomic abnormalities include:# An enlarged clitoris.# Presence of penile urethra or hypospadius.# Associated metabolic abnormality-salt wasting (hyponatremia, hyperkalemia) and hypotension may be present.# Fused vagina.o The presence of any one or more of the above features necessitates further investigations for confirmation of an early diagnosis.