Association of the DAT1 polymorphism with attention deficit hyperactivity disorder (ADHD): a family-based approach.

The dopamine transporter gene (DAT1) is of particular interest in the genetic study of attention deficit hyperactivity disorder (ADHD), because psychostimulants interact directly with the dopamine transporter protein. Association between ADHD and the 10-repeat allele of a 40 base pair (bp) variable number of tandem repeats (VNTR) polymorphism of DAT1 was first reported in 1995 [Cook et al. (1995); Am J Hum Genet 56:993-998]. Subsequently, several investigators have also confirmed this association, although others reported conflicting results. We analyzed the DAT1 polymorphism in a sample of 33 Korean probands with a Diagnostic and Statistical Manual of Mental Disorders version IV (DSM-IV) diagnosis of ADHD and found evidence of increased transmission of the 10-repeat allele using transmission disequilibrium test (TDT) (P = 0.001; OR = 7.88, CI = 2.20-28.29). These data support the role of DAT1 in ADHD susceptibility among Asian populations.