In the classic form of 21 hydroxylase deficiency

In the classic form of 21
-
hydroxylase deficiency , genetically female patients present with hypoaldosteronism as well as virilization during infancy
,
and genetically
male patients present with precocious puberty in childhood
.
However this patient likely has a mild
,
nonclassic form of the disease , resulting in the
onset
of symptoms during young adulthood and
the absence of signs of mineralocorticoid deficiency
.
21
-
Hydroxylase deficiency is the
most
common form of congenital adrenal hyperplasia ( CAH )
.
CAH refers
to
various adrenal enzyme
deficiencies that result in decreased concentrations of cortisol with variable effects on mineralocorticoids and androgens
.
Because cortisol is decreased
,
adrenocorticotropic hormone is
increased
,
which explains the hyperplasia present in all
forms of
the disease
.
Incorrect Answers : A . B
(
D
.
and E
.
11
p
-
Hydroxylase ( Choice A ) deficiency is
a rare
form of CAH in which the production of cortisol and aidosterone
are
interrupted later in the pathway in comparison
to
21
-
hydroxylase deficiency
.
The result is decreased cortisol and aldosterone concentrations with an increased concentration of the intermediate mineralocorticoid
,
11
-
deoxycorticosterone
.
11
-
Deoxycorticosterone acts at the
kidney in a manner similar to aldosterone with resultant sodium and water retention and excretion of potassium and protons
.
These clinical manifestations typically begin in childhood and would
not be associated with increased 17
-
hydroxyprogesterone and androstenedione concentrations
.
17 a
-
Hydroxylase
( Choice
B
) deficiency
is a
form of CAH
that decreases the synthesis
of
glucocorticoids and androgens and
therefore
shunts precursors toward the production
of
mineralocorticoids
.
Consequently
,
hyperaldosteronism leads to hypertension and hypokalemia
.
Genetically male patients typically demonstrate ambiguous genitalia and undescended testes
whereas genetically female patients may not demonstrate morphological differences until puberty
,
when their secondary
sex
characteristics
are
underdeveloped
.
Concentrations of
androstenedione and 17
-
hydroxyprogesterone would be decreased
.
3 f
> -
Hydroxysteroid dehydrogenase ( Choice D ) deficiency leads
to
decreased synthesis of mineralocorticoids , glucocorticoids
,
and androgens
.
However
,
an intermediate in the androgen synthetic
pathway , dehydroepiandrosterone ( DHEA ) , is increased ( as a result of decreased metabolism of DHEA by 3
p
-
hydroxysteroid dehydrogenase ) , which can lead to virilization of genetically female
infants ,
children
,
or young adults
( depending
on the
severity of
the
deficiency )
.
However
,
concentrations
of
androstenedione and 17
-
hydroxyprogesterone
would be decreased
.
5
a
-
Reductase ( Choice E ) deficiency leads to abnormal external genitalia
at
birth and underdevelopment of secondary
sex
characteristics in puberty in genetic males
as a
result of decreased
conversion of testosterone to dihydrotestosterone ( DHT )
.
5 a
-
Reductase deficiency affects genetic males only
.
Educational Objective : CAH results from adrenal enzyme deficiencies in the synthesis of cortisol with variable effects on mineralocorticoids and androgens
.