A mentally retarded 14-year-old boy has a long face, large ears, micropenis, and large testes. Chromosome analysis is likely to demonstrate which of the following?
**Core Concept**
The patient's clinical presentation, including mental retardation, long face, large ears, micropenis, and large testes, suggests a genetic disorder involving an imbalance of sex hormones, particularly androgens. This condition is associated with an extra X chromosome in males.
**Why the Correct Answer is Right**
The patient's symptoms are consistent with Klinefelter syndrome, a genetic disorder characterized by the presence of one or more extra X chromosomes in males (47, XXY). This condition is often associated with infertility, gynecomastia, and developmental delays. The extra X chromosome leads to an imbalance of sex hormone production, resulting in elevated levels of estrogen and decreased levels of testosterone, which explains the patient's micropenis and large testes.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the patient's clinical presentation.
* **Option B:** Turner syndrome is a genetic disorder affecting females, characterized by the absence of one X chromosome (45, X). It is not associated with the patient's symptoms.
* **Option C:** This option is not a recognized genetic disorder.
**Clinical Pearl / High-Yield Fact**
Klinefelter syndrome is the most common sex chromosome disorder in males, affecting approximately 1 in 650 males. It is often diagnosed incidentally during a routine physical examination or when the patient seeks medical attention for infertility issues.
**Correct Answer:** C. 47, XXY. Klinefelter syndrome.