The Question is from neet-zoology human-reproduction , and it was created by the author T SAILAJA

Question

A woman presents with primary amenorrhea, underdeveloped secondary sexual characteristics, and a karyotype of 45,X.  Which specific defect within the female reproductive system is MOST directly responsible for her amenorrhea?

T SAILAJA · Accepted Answer

## CORE INFORMATION
✓ **Answer**: B
## CONCEPT FRAMEWORK
 **Primary Concept**: Turner Syndrome and its impact on female reproductive development.
 **Related Topics**: Karyotype, Amenorrhea, Gonadal dysgenesis, Secondary sexual characteristics,  Hormonal imbalances.
 **Prerequisites**: Understanding of the female reproductive system, genetics, and hormonal regulation of menstruation.
## SOLUTION PATHWAY
**Given Information**:
		Primary amenorrhea (absence of menstruation)
		Underdeveloped secondary sexual characteristics (e.g., breast development, pubic hair)
		Karyotype 45,X (Turner Syndrome)
		
**Method & Steps**:
 1. Identify the genetic condition:
  Reasoning: The karyotype 45,X indicates Turner Syndrome, a chromosomal disorder characterized by the absence of one X chromosome.
  Formula/Rule:  None directly applicable; this is a diagnostic interpretation.
 2. Understand the impact of Turner Syndrome on the reproductive system:
  Working: Turner Syndrome results in gonadal dysgenesis, meaning the ovaries fail to develop properly. This leads to a deficiency in estrogen production which is essential for the development of secondary sexual characteristics and menstruation.
  Key Point:  While other issues might be present (like underdeveloped uterus), the root cause of the amenorrhea is the lack of functional ovaries.
 3. Determine the most direct cause of amenorrhea:
  Result: The lack of functional ovaries is the most direct cause of the amenorrhea because they are responsible for estrogen production, which is crucial for the menstrual cycle.
  Verification: The other options are secondary effects or unrelated to the underlying genetic condition.
## OPTION ANALYSIS
[A] :x: Underdeveloped uterus: While often associated with Turner Syndrome, it's a consequence of the lack of ovarian hormones, not the primary cause of amenorrhea.
[B] ✓: Lack of functional ovaries: This is the direct result of the 45,X karyotype and the primary reason for the amenorrhea.
[C] :x: Imperforate hymen: This is a structural blockage that prevents menstrual flow, but it's not the primary defect in Turner Syndrome.
[D] :x: Insufficient GnRH secretion:  While GnRH is involved in the reproductive cycle, the primary problem in Turner Syndrome is the ovarian failure, leading to insufficient estrogen production, regardless of GnRH levels.
## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing the consequences of Turner Syndrome with its primary cause:  Focusing on the underdeveloped uterus instead of the dysfunctional ovaries.
  2.Overlooking the genetic basis of the condition: Failing to connect the 45,X karyotype to the underlying ovarian dysgenesis.
 **Quick Tips**:
  1.Remember that Turner Syndrome (45,X) is characterized by ovarian dysgenesis.
  2.The lack of functional ovaries directly leads to estrogen deficiency, causing both amenorrhea and underdeveloped secondary sexual characteristics.

T SAILAJA · Answer

Underdeveloped uterus

T SAILAJA · Answer

The correct Option is "Lack of functional ovaries"

T SAILAJA · Answer

Imperforate hymen

T SAILAJA · Answer

Insufficient GnRH secretion

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