Which of the following disorder is caused by autosomal aneuploidy

Options

A. Down 's syndrome
B. Haemophilia
C. Sickle cell anemia
D. Phenylketonuria

Answer

### Step-by-Step Solution

1. **Understanding Autosomal Aneuploidy**:
- Autosomal aneuploidy refers to a condition where there is a change in the number of autosomes (non-sex chromosomes) in an organism. In humans, the normal chromosome number is 46 (23 pairs). Aneuploidy can involve either a loss (monosomy) or gain (trisomy) of chromosomes, leading to a total of 45, 47, or other variations.

2. **Analyzing the Options**:
- We have four options to evaluate: Down syndrome, Hemophilia, Sickle cell anemia, and Phenylketonuria.

3. **Option A: Down Syndrome**:
- Down syndrome is caused by trisomy of chromosome 21, meaning there is an extra chromosome (47 total). This condition is a classic example of autosomal aneuploidy.

4. **Option B: Hemophilia**:
- Hemophilia is an X-linked recessive disorder caused by a mutation in a gene on the X chromosome. There is no change in the overall number of chromosomes, so this is not an example of autosomal aneuploidy.

5. **Option C: Sickle Cell Anemia**:
- Sickle cell anemia is an autosomal recessive disorder caused by a mutation in the gene for the beta-globin chain on chromosome 11. Again, there is no change in chromosome number, so this does not qualify as autosomal aneuploidy.

6. **Option D: Phenylketonuria (PKU)**:
- PKU is also an autosomal recessive disorder caused by a mutation in the gene on chromosome 12. Like the previous two options, there is no change in chromosome number, thus it is not an example of autosomal aneuploidy.

7. **Conclusion**:
- The only disorder among the options that is caused by autosomal aneuploidy is **Down syndrome** (Option A).

### Final Answer:
**Down syndrome** is the disorder caused by autosomal aneuploidy.

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