title: Association between Dopamine D4 Receptor Gene Polymorphism and Scores on a Continuous Performance Test in Korean Children with Attention Deficit Hyperactivity Disorder.
abstract: OBJECTIVE
  The aim of this study was to evaluate the association between a variable number of tandem repeats polymorphism at the dopamine D4 receptor gene (DRD4) and the performance of children with attention deficit hyperactivity disorder (ADHD) in a continuous performance test (CPT).
  
  
  METHODS
  This study included 72 ADHD children (mean age=9.39+/-2.05 years) who were recruited from one child psychiatric clinic. The omission errors, commission errors, reaction time and reaction standardization in the CPT were computed. The number of 48-base pairs tandem repeats in the exon III of DRD4 was analyzed in a blind manner.
  
  
  RESULTS
  The homozygosity of the 4-repeat allele at DRD4 was significantly associated with fewer commission errors (t=2.364, df=28.685, p=0.025) and standard deviation of reaction time (t=2.351, df=24.648, p=0.027) even after adjusting for age. The results of analyses of CPT measured values among three groups showed that the group with higher frequency of the 4-repeat allele showed a lower mean score of commission errors (F=4.268, df=2, p=0.018).
  
  
  CONCLUSIONS
  These results suggest a protective role of 4-repeat allele of the DRD4 polymorphisms on commission errors in the CPT in children with ADHD.
authors.affiliation: Department of Psychiatry, Kwandong University College of Medicine, Goyang, Korea.
authors.forename: Bora
authors.initials: B
authors.lastname: Kim
authors.forename: Min-Seong
authors.initials: MS
authors.lastname: Koo
authors.forename: Jin-Yong
authors.initials: JY
authors.lastname: Jun
authors.forename: Il Ho
authors.initials: IH
authors.lastname: Park
authors.forename: Dong-Yul
authors.initials: DY
authors.lastname: Oh
authors.forename: Keun-Ah
authors.initials: KA
authors.lastname: Cheon