Association of dopamine D4 receptor (DRD4) gene with attention-deficit/hyperactivity disorder (ADHD) in a high-risk community sample: a longitudinal study from birth to 11 years of age.
BACKGROUND
In recent years, a growing number of studies has focused on the dopamine D4 receptor gene (DRD4) as mediating the susceptibility to attention-deficit/hyperactivity disorder (ADHD). While their results are contradictory, the reason for this inconsistency remains as yet unclear.


METHODS
The present study sought to examine the association between ADHD and the DRD4 exon III polymorphism during child development using longitudinal data from a high-risk community sample (n = 265, 129 females, 126 males) who have been followed from birth to 11 years of age.


RESULTS
Higher rates of ADHD were observed in boys with the 7 repeat allele of exon III than in boys with other alleles at the ages of 4 1/2 (Fisher's exact test, p = .061), 8 (p = .026), and 11 years (p = .005). Boys with this allele also exhibited higher rates of persistent disorder (p = .024). In girls, a trend towards an association (p = .055) with the 7 repeat allele emerged only at preschool age.


CONCLUSIONS
These findings provide additional evidence for the role of the dopamine D4 receptor in ADHD during the course of child development.
El-Faddagh
M
M
Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Mannheim, Germany.
Laucht
M
M
Maras
A
A
Vöhringer
L
L
Schmidt
M H
MH
D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics* / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4; D012111:Residence Characteristics / Q000706:statistics & numerical data; D012307:Risk Factors
C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4