- Lower levels of DRD2 because of change in regulatory region of gene. This makes dopamine have more of an effect on the brain (G) (R).
- Normal levels of DRD2 protein in the body (A) (R).
The Minor "G" allele is associated with:
- Increased risk of migraines (R)
- Improved response to haloperidol (R)
- Increased risk of smoking at younger ages (R)
The Major "A" allele is involved with: