Which of the following statements about 21 alpha hydroxylase deficiency is false –
**Core Concept**
21 alpha hydroxylase deficiency is a congenital adrenal hyperplasia (CAH) due to a deficiency of the enzyme 21-hydroxylase, which is crucial for converting 17-hydroxyprogesterone to 11-deoxycortisol in the adrenal cortex. This enzyme deficiency impairs the production of cortisol and aldosterone, leading to an overproduction of androgens.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of 21 alpha hydroxylase deficiency. The enzyme 21-hydroxylase is encoded by the CYP21A2 gene, which is located on chromosome 6p21.3. A mutation in this gene leads to a deficiency of the enzyme, resulting in a decreased production of cortisol and aldosterone. This deficiency is associated with an overproduction of androgens, such as testosterone and dehydroepiandrosterone sulfate (DHEA-S), which can lead to virilization in affected females.
**Why Each Wrong Option is Incorrect**
**Option A:** This statement might be true, as 21 alpha hydroxylase deficiency is a common cause of CAH, and it is associated with an increased risk of salt-wasting and hypotension in the neonatal period.
**Option B:** This statement is also true, as the deficiency of 21-hydroxylase leads to an overproduction of androgens, which can cause virilization in affected females.
**Option C:** This statement is actually true, as 21 alpha hydroxylase deficiency is a genetic disorder that is inherited in an autosomal recessive manner.
**Option D:** This statement is false, as 21 alpha hydroxylase deficiency is not associated with an increased risk of hypertension. In fact, the deficiency of aldosterone can lead to a decreased blood pressure.
**Clinical Pearl / High-Yield Fact**
The classic clinical presentation of 21 alpha hydroxylase deficiency includes virilization in females, hypertension, and hypokalemia in the salt-wasting form, and precocious puberty in both males and females. Early diagnosis and treatment are essential to prevent long-term complications.
**Correct Answer:** D.