Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD .
Speed of processing , set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers .
High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity .
BACKGROUND We review ed systematic ally the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder ( ADHD ) and neuropsychological traits relevant for this disorder .
Functional effects of the DAT1 polymorphism on EEG measures in ADHD.
OBJECTIVE This paper examines whether dopamine transporter gene ( DAT1 ) allele status mediates medication-related change in cognitive and neurophysiological measures among children with attention-deficiency/hyperactivity disorder ( ADHD ) . METHOD A single 10-mg dose of methylpheni date was given in a double-blind , placebo-controlled fashion to children with ADHD who were seen for cognitive testing and EEG recording . Buccal sample s were obtained and genotyped for the DAT1 polymorphism . RESULTS DAT1 allele status was associated with performance on a sustained attention task and medication-related EEG changes . Compared with those with one or more copies of the DAT1 9-repeat allele ( 9R ) , children with two copies of the 10-repeat allele ( 10R ) exhibited poorer performance on the vigilance task . In addition , children with 10R exhibited medication-related EEG changes of increased central and parietal beta power , decreased right frontal theta power , and lower theta/beta ratios ; 9R carriers showed the opposite pattern . CONCLUSIONS The data suggest that the DAT1 polymorphism mediates medication-related changes in cortical activity among children with ADHD
Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD .
Speed of processing , set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers .
High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity .
BACKGROUND We review ed systematic ally the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder ( ADHD ) and neuropsychological traits relevant for this disorder .