Select correct option w.r.t. trisomy aneuploidy

Options

A. Down's syndrome
B. Klinefeller's syndrome
C. turner's syndrome
D. All except (3)

Answer

To solve the question regarding trisomy aneuploidy, we will analyze each option provided and determine which one correctly represents an example of trisomy aneuploidy.

### Step-by-Step Solution:

1. **Understanding Trisomy Aneuploidy**:
- Trisomy aneuploidy refers to a condition where there is an extra chromosome present in the cells, leading to a total of three copies of a particular chromosome instead of the normal two.
- This condition occurs due to nondisjunction during cell division, which results in an abnormal number of chromosomes.

2. **Analyzing the Options**:
- **Option A: Down Syndrome**:
- Down syndrome is characterized by the presence of an extra copy of chromosome 21, making it trisomy 21. This is a classic example of trisomy aneuploidy.
- **Option B: Klinefelter Syndrome**:
- Klinefelter syndrome occurs in males who have an extra X chromosome (XXY instead of XY). This condition does not fit the definition of trisomy aneuploidy as it involves sex chromosomes and not an additional copy of an autosome.
- **Option C: Turner Syndrome**:
- Turner syndrome affects females and is characterized by the absence of one X chromosome (X0). This is not a case of trisomy but rather a monosomy, so it does not qualify as trisomy aneuploidy.
- **Option D: All Except Three**:
- This option suggests excluding the third option (Turner syndrome). However, since Down syndrome is a clear example of trisomy aneuploidy, this option is misleading and incorrect.

3. **Conclusion**:
- After analyzing all the options, the only correct example of trisomy aneuploidy is **Down Syndrome** (trisomy 21).

### Final Answer:
The correct option with respect to trisomy aneuploidy is **Down Syndrome**.