title: Association of dopamine D4 receptor (DRD4) exon III repeat polymorphism with temperament in 3-year-old infants.
abstract: The long forms of the dopamine D4 receptor (DRD4) exon III repeat polymorphism (L-DRD4) have been linked in some studies to the adult personality trait of novelty seeking (NS), as well as to infant personality traits related to interest and activity. The current investigation extends the results of our previous longitudinal study on 1- to 5-month-old neonates assessed by the Early and Revised Infancy Temperament Questionnaire (EITQ/RITQ), in which we found a significant correlation between the DRD4 polymorphism and the adaptability trait at 1 month of age. In this study, we examined the relationship between children's behavior at 3 years of age, measured with the Toddler Temperament Scale (TTS), and DRD4 exon III repeat polymorphism. We found a significant association between the behavioral dimension of intensity of reaction and DRD4 genotypes. Current data failed to confirm the association with the adaptability trait. None of the extraversion and/or exploratory behavior measures was related to the L-DRD4 allele, as expected. In contrast, children with 4/7 genotypes showed worse response to new stimuli compared with 4/4 genotypes. This study corroborates only in part previous results on the link between the DRD4 gene and human temperament.
authors.affiliation: IRCCS-CSS, San Giovanni Rotondo and CSS-Mendel Institute, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: De Luca
authors.forename: Mario
authors.initials: M
authors.lastname: Rizzardi
authors.forename: Anna
authors.initials: A
authors.lastname: Buccino
authors.forename: Rosina
authors.initials: R
authors.lastname: Alessandroni
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Salvioli
authors.forename: Nando
authors.initials: N
authors.lastname: Filograsso
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Novelli
authors.forename: Bruno
authors.initials: B
authors.lastname: Dallapiccola
mesh_terms: D002652:Child Behavior / Q000502:physiology*; D002675:Child, Preschool; D005091:Exons; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4; D013694:Temperament / Q000502:physiology*
chemical_list: C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4