Structural correlates of COMT Val158Met polymorphism in childhood ADHD: a voxel-based morphometry study

Area of Science:

• Neuroscience
• Genetics
• Child Psychology

Background:

• The Val158Met polymorphism in the catechol-O-methyltransferase (COMT) gene (rs4680) is associated with antisocial behavior in attention-deficit/hyperactivity disorder (ADHD).
• Understanding the neurobiological underpinnings of this association is crucial for targeted interventions.

Purpose of the Study:

• To investigate the impact of the COMT Val158Met polymorphism on grey matter (GM) volumes in children with ADHD.
• To explore how this genetic variation influences brain structure in relation to ADHD symptoms.

Main Methods:

• Voxel-based morphometry (VBM) was employed to analyze MRI data from 38 children with combined-type ADHD and 24 typically developing (TD) children.
• Genotype data for the COMT Val158Met polymorphism were obtained.
• Regions of interest included the striatum, cerebellum, temporal lobe, and inferior frontal gyrus (IFG).

Main Results:

• Children with ADHD exhibited significantly reduced GM volume in the IFG compared to TD children.
• IFG volume was negatively correlated with hyperactivity/impulsivity symptom ratings.
• The reduction in IFG GM volume was specifically linked to the Met158-allele in children with ADHD.
• Children with ADHD homozygous for the Val158-allele showed increased GM volume in the caudate nucleus compared to TD children.

Conclusions:

• This study provides the first evidence that the COMT Val158Met polymorphism modulates ADHD-related grey matter alterations.
• These findings suggest that the Val158Met polymorphism may mediate the relationship between ADHD and antisocial behavior through its effects on specific brain regions like the IFG and caudate nucleus.