Association of polymorphisms in the dopamine D4 receptor gene and the activity-impulsivity endophenotype in dogs

K. Hejjas, J. Vas, J. Topal, E. Szantai, Z. Ronai, A. Szekely, E. Kubinyi, Z. Horvath, M. Sasvari-Szekely, A. Miklosi

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72 Citations (Scopus)


A variable number of tandem repeats (VNTR) polymorphism in exon 3 of the human dopamine D4 receptor gene (DRD4) has been associated with attention deficit hyperactivity disorder (ADHD). Rodents possess no analogous repeat sequence, whereas a similar tandem repeat polymorphism of the DRD4 gene was identified in dogs, horses and chimpanzees. Here, we present a genetic association study of the DRD4 VNTR and the activity-impulsivity dimension of the recently validated dog-ADHD Rating Scale. To avoid false positives arising from population stratification, a single breed of dogs (German shepherd) was studied. Two DRD4 alleles (referred to as 2 and 3a) were detected in this breed, and genotype frequencies were in Hardy-Weinberg equilibrium. For modelling distinct environmental conditions, 'pet' and 'police' German shepherds were characterized. Police German shepherds possessing at least one 3a allele showed significantly higher scores in the activity-impulsivity dimension of the dog-ADHD Rating Scale than dogs without this allele (P = 0.0180). This difference was not significant in pet German shepherds. To the best of our knowledge, this is the first report of an association between a candidate gene and a behaviour trait in dogs, and it reinforces the functional role of DRD4 exon 3 polymorphism.

Original languageEnglish
Pages (from-to)629-633
Number of pages5
JournalAnimal Genetics
Issue number6
Publication statusPublished - Dec 1 2007



  • Activity-impulsivity
  • Dog
  • Dopamine D4 receptor gene
  • Genetic association
  • Polymorphism

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Genetics

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