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. METHOD: 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.
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. METHOD: 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.
Authors: Kate Langley; Tom A Fowler; Deborah L Grady; Robert K Moyzis; Peter A Holmans; Marianne B M van den Bree; Michael J Owen; Michael C O'Donovan; Anita Thapar Journal: Eur Child Adolesc Psychiatry Date: 2008-06-18 Impact factor: 4.785