Determining the association between polymorphisms of the DAT1 and DRD4 genes with attention deficit hyperactivity disorder in children from Java Island

Abstract

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurobehavioural in the children. Genetic factor is known one of the factors which contributed in ADHD development. VNTR polymorphism in 3’UTR exon 15 of DAT1 gene and exon 3 of DRD4 gene are reported to be associated in ADHD. In this study we examine the association of ADHD with VNTR polymorphism of DAT1 and DRD4 gene in Indonesian children. Sixty-five ADHD children and 70 normal children (6- 13 years of age), were included in the study, we matched by age and gender. ADHD was diagnosed by DSM-IV. We performed a casecontrol study to found the association between ADHD and VNTR polymorphism of DAT1 and DRD4 genes. The 10-repeat allele of DAT1 and 2-repeat allele of DRD4 were higher in Indonesian children. Although the frequency of these allele was higher, but it was similar both in ADHD and control groups. Neither DAT1 nor DRD4 gene showed showed significant difference in genotype distribution and frequency allele between both groups (p > 0.05). No association between ADHD and VNTR polymorphism of DAT1 and DRD4 genes found in Indonesian children. This data suggest that DAT1 and DRD4 do not contribute to etiology of ADHD in Indonesian children. Further studies are needed to clarify association between VNTR polymorphism of DAT1 and DRD4 genetic with ADHD of Indonesian children in larger sample size and family based study.