A genetic variant is a change of nucleotides in the DNA sequence that forms a gene. This change can have different impacts:
- Negative impact, increasing the risk of developing a disease.
- Positive impact, reducing said risk.
- Neutral impact. This is the most common.
A genetic variant implies that this region of DNA is different from the most common sequence in the reference population. However, the same variant can be found in several individuals within that same population.
Variants are permanent and are not always inherited. When a variant occurs in an individual but not in their parents, it is called "de novo."