|Bora Kim1;Min-Seong Koo1;Jin-Yong Jun2;Il Ho Park1;Dong-Yul Oh1; and Keun-Ah Cheon1;
1;Department of Psychiatry, Kwandong University College of Medicine, Goyang,
2;Settlement Support Center for Dislocated North Koreans, Ministry of Unification, Anseong, Korea
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).
Conclusion : These results suggest a protective role of 4-repeat allele of the DRD4 polymorphisms on commission errors in the CPT in children with ADHD.
Attention deficit hyperactivity disorder;Continuous performance test;Dopamine D4 receptor;4 repeats allele;Commission errors.