[size=20px]A prenatal diagnosis of 21-hydroxylase deficiency is established by amniocentesis for a 25-week gestation male fetus whose parents had another child who died shortly after birth.

 

Which of the following clinical presentations is inconsistent with his 21-hydroxylase deficiency diagnosis?

 

A ambiguous genitalia

 

B failure to thrive in the newborn period

 

C premature virilization prior to puberty

 

D dehydration, hyperkalemia, hyponatremia and shock in the newborn period

 

E symptoms of pyloric stenosis or gastroenteritis in the early newborn period[/size]

e

think again my dear

A

A

A

(Untitled)

 

'A' is inconsitent with the above scenerio because it is an XY baby. And the condition that has been mentioned here will cause excessive masculinization. But the biochemical abnormalities and clinical features will be same in either sex. Male CAH may be more suceptible to be missed because of the abscence of sexual ambiguity.

Correct answer

A ambiguous genitalia

 

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder of cholesterol metabolism due to enzymatic defects. The adrenal 21-hydroxylase (21-OH) enzyme is one of five enzymes necessary for the synthesis of cortisol from cholesterol and its deficiency is the most common enzymatic defect causing CAH. 21-OH deficiency (21-OHD) occurs in a classical form that can cause masculinization and genital ambiguity at birth in genetic females.

 

In the absence of a prenatal diagnosis, 21-hydroxylase deficiency in males is often not identified in the neonatal period because the genitalia are normal. Presentation depends on the severity of the defect in steroid and/or mineralocorticoid production. Severe forms may develop classic early salt-wasting adrenal hyperplasia (hyponatremia, hyperkalemia, vomiting, dehydration and hypotension). Salt wasting forms of CAH may also have elevated plasma renin activity (PRA) and decreased serum aldosterone.

 

Failure to thrive or misdiagnosis with pyloric stenosis or gastroenteritis may be seen in less severe defects. Milder forms may result in virilization in childhood with the presence of pubic hair, phallus enlargement and premature skeletal maturation.

 

Fetal 21-OHD can be identified by chorionic villus sampling (CVS) or amniocentesis. Prenatal treatment of 21-OHD with steroids (20 mcg/kg/d of dexamethasone divided into 3 doses) has been used on an off-label, experimental basis for approximately 15 years to suppress fetal ACTH and androgen production. However, a genetically male fetus would not be a candidate for prenatal steroid treatment

A

A

ambiguous genitalia just occur in female