Catechol-o-methyltransferase gene and executive function in children with ADHD

Area of Science:

• Neurogenetics
• Child Psychiatry
• Cognitive Neuroscience

Background:

• Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder.
• Executive functions (EF) are often impaired in children with ADHD.
• The catechol-o-methyltransferase (COMT) gene plays a role in dopamine regulation, a neurotransmitter implicated in ADHD and EF.

Purpose of the Study:

• To investigate the association between functional haplotypes of the COMT gene and ADHD diagnosis.
• To examine the relationship between COMT gene variations and specific executive function (EF) measures in children with ADHD.

Main Methods:

• Genotyping of COMT single nucleotide polymorphisms (SNPs: rs6269, rs4633, rs4818, rs4680) in 445 children diagnosed with ADHD.
• Assessment of EF using the Wisconsin Card Sorting Test (WCST), Tower of London, and self-ordered pointing task.
• Association analyses using family-based association testing (fBAT) and quantitative trait analyses.

Main Results:

• No significant association was found between COMT alleles/haplotypes and ADHD diagnosis or EF parameters via fBAT.
• In Caucasian participants, ANCOVA revealed significant associations between COMT haplotypes and WCST indices.
• After multiple testing correction, only the association between rs6269 and WCST categories completed (concept formation) remained significant (p = .003).

Conclusions:

• The COMT gene is tentatively implicated in the modulation of executive functions in children with ADHD.
• Specific COMT variants, particularly rs6269, may influence concept formation abilities in ADHD.
• Further investigation is warranted to elucidate the precise role of COMT in ADHD-related executive function deficits.