Background: The adoption of neuropsychological tests as endophenotypic measures can provide an increased sensitivity to specific dimensions of attention-deficit/hyperactivity disorder (ADHD).
Methods: The association between a variable number of tandem repeats polymorphism at the dopamine D4 receptor gene (DRD4) and the performance of children and adolescents with ADHD in a continuous performance test (CPT) was evaluated. The sample comprised 90 clinically referred children and adolescents with ADHD. Errors of omission and commission in the CPT were computed and the number of 48-base pairs tandem repeats in the exon III of DRD4 was assessed.
Results: The presence of a 7-repeat allele was associated with more errors of commission and the homozygosity of the 4-repeat allele was related to fewer errors of commission and omission even after adjusting for age.
Conclusions: These findings bring further evidence on the role of DRD4 polymorphisms on the performance in sustained attention tasks among children and adolescents with ADHD diagnosis.