Catechol-O-methyltransferase (COMT) Val108/158 Met polymorphism does not modulate executive function in children with ADHD.
BACKGROUND
An association has been observed between the catechol-O-methyltransferase (COMT) gene, the predominant means of catecholamine catabolism within the prefrontal cortex (PFC), and neuropsychological task performance in healthy and schizophrenic adults. Since several of the cognitive functions typically deficient in children with Attention Deficit Hyperactivity Disorder (ADHD) are mediated by prefrontal dopamine (DA) mechanisms, we investigated the relationship between a functional polymorphism of the COMT gene and neuropsychological task performance in these children.


METHODS
The Val108/158 Met polymorphism of the COMT gene was genotyped in 118 children with ADHD (DSM-IV). The Wisconsin Card Sorting Test (WCST), Tower of London (TOL), and Self-Ordered Pointing Task (SOPT) were employed to evaluate executive functions. Neuropsychological task performance was compared across genotype groups using analysis of variance.


RESULTS
ADHD children with the Val/Val, Val/Met and Met/Met genotypes were similar with regard to demographic and clinical characteristics. No genotype effects were observed for WCST standardized perseverative error scores [F2,97 = 0.67; p > 0.05], TOL standardized scores [F2,99 = 0.97; p > 0.05], and SOPT error scores [F2,108 = 0.62; p > 0.05].


CONCLUSIONS
Contrary to the observed association between WCST performance and the Val108/158 Met polymorphism of the COMT gene in both healthy and schizophrenic adults, this polymorphism does not appear to modulate executive functions in children with ADHD.
Taerk
Evan
E
Department of Psychiatry, McGill University and Douglas Hospital Research Centre, Montreal, Quebec, H4H 1R3, Canada. evantaerk@yahoo.ca.
Grizenko
Natalie
N
Ben Amor
Leila
L
Lageix
Philippe
P
Mbekou
Valentin
V
Deguzman
Rosherie
R
Torkaman-Zehi
Adam
A
Ter Stepanian
Marina
M
Baron
Chantal
C
Joober
Ridha
R
D019943:Amino Acid Substitution / Q000235:genetics; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000201:enzymology* / Q000235:genetics* / Q000523:psychology; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D002648:Child; D004298:Dopamine / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008715:Methionine / Q000235:genetics*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011110:Polymorphism, Genetic / Q000502:physiology*; D017397:Prefrontal Cortex; D014633:Valine / Q000235:genetics*
D008715:Methionine; D002394:Catechol O-Methyltransferase; D014633:Valine; D004298:Dopamine