Precocious puberty is seen in all except –
**Core Concept**
Precocious puberty refers to the premature onset of pubertal changes, typically before the age of 8 in girls and 9 in boys. This condition can be caused by various factors, including genetic disorders, tumors, and hormonal imbalances.
**Why the Correct Answer is Right**
Precocious puberty can be triggered by central nervous system disorders, such as McCune-Albright syndrome, which involves a mutation in the GNAS gene leading to excessive production of gonadotropin-releasing hormone (GnRH) and subsequent activation of the hypothalamic-pituitary-gonadal (HPG) axis. Other causes include central nervous system tumors, such as craniopharyngiomas, which can disrupt normal hypothalamic function and lead to precocious puberty.
**Why Each Wrong Option is Incorrect**
**Option A:** McCune-Albright syndrome is a known cause of precocious puberty, so this option is incorrect.
**Option B:** Central nervous system tumors, such as craniopharyngiomas, can also cause precocious puberty, making this option incorrect.
**Option C:** Certain genetic disorders, such as Klinefelter syndrome, can be associated with precocious puberty, so this option is incorrect.
**Clinical Pearl / High-Yield Fact**
It's essential to distinguish between central and peripheral precocious puberty, as the underlying cause and treatment approach differ significantly. Central precocious puberty is typically treated with GnRH agonists, whereas peripheral precocious puberty may require hormone replacement or other targeted therapies.
**Correct Answer: D.**