**Question:** A 25-year-old woman presented with primary amenorrhea, short stature, webbed neck, broad chest, and widely spaced nipples. Examination showed weak pulses in the lower extremities and streak ovaries. Which of the following karyotype is most likely to be present?

A. 46, XX
B. 46, XY
C. 45, X
D. 47, XXXY

**Correct Answer:** C. 45, X

**Core Concept:** Karyotype refers to the chromosome count and structure in a cell. In humans, the normal karyotype is 46 chromosomes, with 23 pairs of autosomes (46, XX in females and 46, XY in males). Chromosome abnormalities are associated with specific clinical features and can be used to diagnose genetic disorders.

**Why the Correct Answer is Right:** The correct answer is 45, X because this karyotype is associated with Turner syndrome, a genetic disorder caused by the presence of a partial or complete absence of one of the two X chromosomes. Turner syndrome primarily affects females and is characterized by short stature, webbed neck, and broad chest due to the absence of the X chromosome.

**Why Each Wrong Option is Incorrect:**

A. 46, XX (normal female karyotype) - This option is incorrect because the patient does not have the clinical features of Turner syndrome and is not characterized by short stature, webbed neck, and broad chest.

B. 46, XY (normal male karyotype) - This option is incorrect because the patient is female and does not have the clinical features of Turner syndrome.

D. 47, XXXY (Klinefelter syndrome) - This option is incorrect because Klinefelter syndrome occurs in males and is characterized by tall stature, gynecomastia, and poor muscle mass development. The patient described in the question does not present with these features.

**Clinical Pearls:**

Turner syndrome is a genetic disorder that affects females due to the absence of one of the X chromosomes. Its clinical features include short stature, webbed neck, and broad chest. Turner syndrome is usually diagnosed in childhood or early adolescence, and management involves hormone replacement therapy, growth hormone, and dental and cardiac care. Early diagnosis and intervention can help improve the patient's quality of life and prevent complications.