From regulatory problems in infancy to attention-deficit/hyperactivity disorder in childhood: a moderating role for the dopamine D4 receptor gene?
OBJECTIVE
To examine whether the dopamine receptor D4 gene (DRD4) exon III VNTR moderates the risk of infants with regulatory disorders for developing attention-deficit/hyperactivity disorder (ADHD) later in childhood.


METHODS
In a prospective longitudinal study of children at risk for later psychopathology, 300 participants were assessed for regulatory problems in infancy, DRD4 genotype, and ADHD symptoms and diagnoses from childhood to adolescence. To examine a potential moderating effect on ADHD measures, linear and logistic regressions were computed. Models were fit for the main effects of the DRD4 genotype (presence or absence of the 7r allele) and regulatory problems (presence or absence), with the addition of the interaction term. All models were controlled for sex, family adversity, and obstetric risk status.


RESULTS
In children without the DRD4-7r allele, a history of regulatory problems in infancy was unrelated to later ADHD. But in children with regulatory problems in infancy, the additional presence of the DRD4-7r allele increased the risk for ADHD in childhood.


CONCLUSIONS
The DRD4 genotype seems to moderate the association between regulatory problems in infancy and later ADHD. A replication study is needed before further conclusions can be drawn, however.
Becker
Katja
K
Department of Child and Adolescent Psychiatry and Psychotherapy, Medical Faculty, Philipps University Marburg, Marburg, Germany. katja.becker@med.uni-marburg.de
Blomeyer
Dorothea
D
El-Faddagh
Mahha
M
Esser
Guenter
G
Schmidt
Martin H
MH
Banaschewski
Tobias
T
Laucht
Manfred
M
D000293:Adolescent; D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D018730:Infant Behavior; D008297:Male; D011110:Polymorphism, Genetic; D050638:Receptors, Dopamine D4 / Q000235:genetics* / Q000502:physiology
C493599:DRD4 protein, human; D050638:Receptors, Dopamine D4