DRD2 Taq1A Polymorphism-Related Brain Volume Changes in Parkinson's Disease: Voxel-Based Morphometry

Area of Science:

• Neurogenetics
• Neuroimaging
• Neurology

Background:

• The Taq1A polymorphism, a variant of the DRD2 gene within the ANKK1 gene, influences brain dopaminergic functions.
• A1 carriers of the Taq1A polymorphism may face an elevated risk for Parkinson's disease (PD) and exhibit distinct clinical outcomes compared to A2 homozygotes.
• Prior research suggests A1 carriers have reduced dopamine D2 receptors and compensatory cortical hyperactivity in PD.

Purpose of the Study:

• To investigate the association between brain volume and the Taq1A polymorphism in Parkinson's disease patients.
• To explore potential morphological correlates of dopaminergic system variations in PD.

Main Methods:

• Voxel-based morphometry (VBM) was employed to analyze brain morphology.
• 103 Parkinson's disease patients were genotyped for the Taq1A polymorphism.
• Patients were categorized into A1 carriers (A1/A1, A1/A2) and A2 homozygotes (A2/A2).

Main Results:

• A significant reduction in the volume of the left prefrontal cortex (PFC) was observed in A2 homozygotes compared to A1 carriers.
• This volumetric difference suggests a link between Taq1A genotype and brain structure in PD.

Conclusions:

• The Taq1A polymorphism is associated with regional brain volume differences in Parkinson's disease.
• Reduced left PFC volume in A2 homozygotes may reflect underlying neurobiological differences or compensatory mechanisms in A1 carriers.