349vaginal confl uence should undergo vaginoplasty and perineal reconstruction
(with or without clitoroplasty) at an early age. The surgical reconstruction of
high vaginal confl uence is technically more challenging, and the optimal timing
for surgery in children with high vaginal confl uence is not defi ned.- Why does a female fetus with CAH lack development of Wolffi an structures
despite exposure to high levels of androgens during period of genital
differentiation?
Differentiation of external genitalia to male phenotype depends on the exposure to
circulating androgens (predominantly dihydrotestosterone), whereas differentia-
tion of Wolffi an structures is mediated by the paracrine action of androgens (pre-
dominantly testosterone) from the testes. In a female fetus with CAH, exposure to
high levels of circulating adrenal androgens results in the differentiation of exter-
nal genitalia to male phenotype during the period of genital differentiation. As the
source of androgen excess in female fetus with CAH is adrenal and only paracrine
action of testosterone from testes can result in stabilization of Wolffi an structures;
therefore, female fetus with CAH will not develop Wolffi an structures.- What are the features of post-natal virilization in a 46,XX child?
Post-natal exposure to androgens in a girl child will result in clitoral enlarge-
ment, pubarche, acne, and deepening of voice. However, as the urogenital sinus
has already completed differentiation, androgen exposure in the post-natal
period does not result in genital virilization beyond Prader stage 1.- Why pubarche does not occur during infancy despite prenatal androgen excess
in CAH?
CAH is characterized by a high level of androgens during intrauterine and post-
natal period. This results in virilization of external genitalia in newborn girls
and penile enlargement in newborn boys. However, pubic hair appears only
after the age of 2–4 years. This is because priming of pilosebaceous unit (and
hence pubarche) require prolonged and persistent exposure to androgens as
compared to virilization of the urogenital sinus which require only short-term
exposure.- What are the manifestations of simple virilizing CAH due to 21α-hydroxylase
defi ciency?
Girls with simple virilizing CAH due to 21α-hydroxylase defi ciency manifest
with genital ambiguity at birth, whereas affected boys present with premature
pubarche and penile enlargement between 2–4 years of age. Patients with sim-
ple virilizing CAH do not manifest salt-wasting crisis as 1–2 % of residual
21 α-hydroxylase activity is suffi cient to maintain near-normal level of aldoste-
rone. However, if the diagnosis is delayed, girls usually present at peripubertal10 Congenital Adrenal Hyperplasia