Which of the following is not related to sex chromosome X or Y?

Options

A. Turner's syndrome
B. Klinefelter's syndrome
C. Down's syndrome
D. Haemophilia and colour blindness

Answer

To solve the question of which disorder is not related to sex chromosomes X or Y, we will analyze each option provided:

1. **Turner Syndrome**:
- Turner syndrome occurs when a female has only one X chromosome (X0). This condition is directly related to the sex chromosome, as it involves the absence of one X chromosome. Therefore, this option is related to sex chromosomes.

2. **Klinefelter Syndrome**:
- Klinefelter syndrome is characterized by males having an extra X chromosome (XXY). This condition also involves sex chromosomes, as it includes an additional X chromosome. Thus, this option is related to sex chromosomes.

3. **Down Syndrome**:
- Down syndrome is caused by the presence of an extra copy of chromosome 21 (trisomy 21). Chromosome 21 is an autosome, not a sex chromosome. Therefore, Down syndrome is not related to sex chromosomes.

4. **Hemophilia**:
- Hemophilia is a genetic disorder that affects the blood's ability to clot and is linked to mutations on the X chromosome. This condition is directly related to the sex chromosome X.

5. **Color Blindness**:
- Color blindness is also an X-linked condition, meaning it is caused by genes on the X chromosome. Thus, it is related to sex chromosomes.

Based on this analysis, the only disorder that is not related to sex chromosomes X or Y is **Down syndrome**.

**Final Answer**: Down syndrome (Option C).