Quantitative trait locus analysis of candidate gene alleles associated with attention deficit hyperactivity disorder (ADHD) in five genes: DRD4, DAT1, DRD5, SNAP-25, and 5HT1B

Am J Med Genet B Neuropsychiatr Genet. 2005 Feb 5;133B(1):68-73. doi: 10.1002/ajmg.b.30107.


It has been widely postulated that the categorical diagnosis of attention deficit hyperactivity disorder (ADHD) should be seen as the extreme end of a set of traits quantitatively distributed in the general population. A consequence of this is that the genes associated with DSM-IV ADHD should also influence these underlying traits in non-affected individuals. The aim of this study was to examine if specific candidate loci previously shown to be associated with DSM-IV ADHD, also act as quantitative trait loci (QTLs) for ADHD-symptoms in the general population. We have genotyped five candidate markers in a population-based sample of male dizygous twin-pairs (n = 329 pairs). We found little evidence to support a role for the previously-nominated alleles of a DRD4 VNTR, a 5HT1B SNP, or a microsatellite marker near to DRD5, in the distribution of ADHD-symptoms scores; however, we found some evidence to suggest that the DAT1 3'UTR VNTR and weak evidence that a microsatellite in SNAP-25 may have a role in continuous measures of ADHD-symptoms hyperactivity above and beyond their role in clinical ADHD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Attention Deficit Disorder with Hyperactivity / genetics*
  • Child
  • Dopamine Plasma Membrane Transport Proteins
  • Gene Frequency
  • Genetic Predisposition to Disease / genetics*
  • Genotype
  • Humans
  • Linkage Disequilibrium
  • Male
  • Membrane Glycoproteins / genetics
  • Membrane Proteins / genetics
  • Membrane Transport Proteins / genetics
  • Meta-Analysis as Topic
  • Nerve Tissue Proteins / genetics
  • Polymorphism, Genetic
  • Quantitative Trait Loci / genetics*
  • Receptor, Serotonin, 5-HT1B / genetics
  • Receptors, Dopamine D1 / genetics
  • Receptors, Dopamine D2 / genetics
  • Receptors, Dopamine D4
  • Receptors, Dopamine D5
  • Synaptosomal-Associated Protein 25
  • Twins, Dizygotic / genetics*


  • DRD4 protein, human
  • DRD5 protein, human
  • Dopamine Plasma Membrane Transport Proteins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Receptor, Serotonin, 5-HT1B
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2
  • SLC6A3 protein, human
  • SNAP25 protein, human
  • Synaptosomal-Associated Protein 25
  • Receptors, Dopamine D4
  • Receptors, Dopamine D5