A preganant woman who has undergone amniocentesis test, finds an extra Barr body in her embryo. The syndrome which is likely to be associated with embryo is

Options

A. Klinefelter's syndrome
B. Down's syndrome
C. Turner's syndrome
D. Patau's syndrome.

Answer

To solve the question regarding the extra Barr body found in the embryo of a pregnant woman who underwent amniocentesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Barr Bodies**:
- Barr bodies are inactivated X chromosomes found in the cells of females. The number of Barr bodies can be calculated using the formula:
\[ \text{Number of Barr bodies} = n - 1 \]
where \( n \) is the number of X chromosomes.

2. **Identify the Number of X Chromosomes**:
- In normal females, there are 2 X chromosomes (XX), which results in:
\[ 2 - 1 = 1 \text{ Barr body} \]
- In normal males, there is 1 X chromosome (XY), which results in:
\[ 1 - 1 = 0 \text{ Barr bodies} \]

3. **Consider Klinefelter Syndrome**:
- Klinefelter syndrome occurs in males who have an extra X chromosome, resulting in a chromosomal composition of XXY.
- For individuals with Klinefelter syndrome:
\[ n = 2 \text{ (from XXY)} \]
Thus, the number of Barr bodies would be:
\[ 2 - 1 = 1 \text{ Barr body} \]

4. **Evaluate Other Syndromes**:
- **Turner Syndrome**: A female with only one X chromosome (X0) will have:
\[ 1 - 1 = 0 \text{ Barr bodies} \]
- **Down Syndrome**: This is a trisomy of chromosome 21 and does not affect the number of Barr bodies in a typical male or female.
- **Patau Syndrome**: This is a trisomy of chromosome 13 and also does not affect the number of Barr bodies.

5. **Conclusion**:
- Since the embryo has an extra Barr body, it indicates the presence of an extra X chromosome, which is characteristic of Klinefelter syndrome (XXY). Therefore, the likely syndrome associated with the embryo is Klinefelter syndrome.

### Final Answer:
The syndrome likely to be associated with the embryo is **Klinefelter syndrome**.

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