State what does aneuploidy lead to?

Explanation

### Step-by-Step Solution:

1. **Definition of Aneuploidy**:
- Aneuploidy is a chromosomal disorder characterized by an abnormal number of chromosomes in a cell. This can occur due to the addition or deletion of chromosomes from the normal set.

2. **Types of Aneuploidy**:
- There are two main types of aneuploidy:
- **Trisomy**: This is when there is an extra chromosome. For example, Down syndrome is caused by trisomy of chromosome 21, where individuals have three copies of chromosome 21 instead of the normal two.
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