Variants of the SLC6A3 (DAT1) polymorphism affect performance monitoring-related cortical evoked potentials that are associated with ADHD.

Although the 10-repeat (10R) variant of the dopamine transporter gene (DAT1 or SLC6A3) is suggested to be a risk allele for Attention Deficit Hyperactivity Disorder (ADHD) no relationships between DAT1 and measures of cognition in children with ADHD have yet been demonstrated. We studied neurophysiological correlates of performance monitoring during a feedback-based learning task by measuring cortical event-related potentials (ERPs) in a group of 65 10-13-year-old children half of whom were diagnosed as ADHD. The first part of the study investigates correlations between parent-reported behaviour problems and several performance monitoring components, while the second part investigates the relationship between DAT1 and these components. Specifically ADHD problems correlated significantly with an error-related positivity (Pe) and a feedback-anticipatory negativity (the SPN). Only these two components discriminated between the DAT1 10/10R and 9R carriers. The 10/10R carriers showed a smaller Pe to errors and a smaller SPN in anticipation of negative feedback, particularly with learning.