A 21 year old woman presents with complaints of primary amenorrhoea. Her height is 153 cms, weight is 51 kg. She has well developed breasts. She has no pubic or axillary hair and no hirsuitism. Which of the following is the most probable diagnosis?
**Core Concept**
The patient's presentation of primary amenorrhoea, well-developed breasts, but absence of pubic or axillary hair and no hirsutism suggests a disorder of sex development, specifically a condition where there is a discrepancy between the chromosomal and gonadal sex.
**Why the Correct Answer is Right**
The patient's symptoms are suggestive of Turner syndrome, a genetic disorder characterized by the absence of one X chromosome (45,X). This leads to ovarian dysgenesis, resulting in estrogen production but not sufficient to stimulate the development of secondary sexual characteristics such as pubic and axillary hair. The presence of well-developed breasts is due to estrogen produced by the remaining ovarian tissue.
**Why Each Wrong Option is Incorrect**
* **Option A:** Androgen insensitivity syndrome (AIS) typically presents with well-developed secondary sexual characteristics and no breasts due to the body's inability to respond to androgens, which is not the case in this patient.
* **Option B:** Klinefelter syndrome (47,XXY) typically presents with tall stature, sparse body hair, and gynecomastia, but this patient is short and has no hirsutism.
* **Option C:** Congenital adrenal hyperplasia (CAH) typically presents with virilization of the external genitalia and no well-developed breasts, which is not the case in this patient.
* **Option D:** Swyer syndrome (46,XY with ovarian dysgenesis) typically presents with well-developed breasts and no secondary sexual characteristics, which is more consistent with this patient's presentation.
**Clinical Pearl / High-Yield Fact**
Turner syndrome is often associated with short stature, which can be treated with growth hormone therapy. Patients with Turner syndrome are also at increased risk of developing autoimmune disorders, such as Hashimoto thyroiditis.
**Correct Answer:** C.