Klinefelter’s syndrome is diagnosed by:
**Core Concept**
Klinefelter's syndrome is a genetic disorder characterized by the presence of an extra X chromosome in males, leading to infertility, developmental delays, and various physical characteristics. The syndrome is caused by aneuploidy, specifically 47,XXY karyotype. The condition is often associated with hormonal imbalances, particularly hypogonadism.
**Why the Correct Answer is Right**
The correct answer is **C. Karyotype analysis**. Karyotype analysis is the gold standard for diagnosing Klinefelter's syndrome. It involves examining the chromosomes of the individual to identify the 47,XXY pattern. This test can be performed on blood or tissue samples. The presence of an extra X chromosome confirms the diagnosis of Klinefelter's syndrome.
**Why Each Wrong Option is Incorrect**
* **Option A:** Physical examination and clinical evaluation alone are not sufficient to diagnose Klinefelter's syndrome. While individuals with the syndrome may exhibit physical characteristics such as tall stature, gynecomastia, and infertility, these signs are not unique to the condition and can be present in other disorders.
* **Option B:** Hormone level assessment, such as testosterone or FSH measurement, can be used to support the diagnosis of Klinefelter's syndrome. However, these tests are not definitive and can be abnormal in other conditions as well.
* **Option D:** Genetic testing, such as PCR or FISH, can be used to identify the extra X chromosome. However, these tests are not as widely available as karyotype analysis and may not be necessary for diagnosis.
**Clinical Pearl / High-Yield Fact**
It's essential to note that Klinefelter's syndrome can be diagnosed at various ages, including childhood, adolescence, and adulthood. Early diagnosis and treatment can improve fertility outcomes and overall quality of life for individuals with the syndrome.
**Correct Answer:** C. Karyotype analysis