title: Association of DRD4 in children with ADHD and comorbid conduct problems.
abstract: Recent family and twin study findings suggest that ADHD when comorbid with conduct problems may represent a particularly familial and heritable form of ADHD. Although several independent groups have shown association between the DRD4 7 repeat allele and ADHD, others have failed to replicate this finding. Previous TDT analyses of UK and Eire samples had also been negative. We set out to further examine the role of DRD4 but selecting a subgroup of children with ADHD and comorbid conduct problems. Families were recruited from Manchester, Ireland, Birmingham and London clinics. From these, 67 children who fulfilled diagnostic criteria for ADHD and who displayed conduct disorder symptoms were selected. TDT analysis, which had previously yielded negative results for the total sample, showed evidence of association between DRD4 and "ADHD with conduct problems" (7 repeat allele-24 transmissions, 13 non-transmissions; one-tailed P=0.05). These results provide further support for the role of DRD4 in ADHD. Furthermore, these results when considered together with family and twin study findings, suggest that those children with ADHD and comorbid conduct problems may be particularly informative for molecular genetic studies of ADHD. Further work is needed to examine these phenotype issues.
authors.affiliation: Department of Psychological Medicine, University of Wales College of Medicine, Heath Park, Cardiff, Wales, United Kingdom.
authors.forename: Jane
authors.initials: J
authors.lastname: Holmes
authors.forename: Antony
authors.initials: A
authors.lastname: Payton
authors.forename: Jennifer
authors.initials: J
authors.lastname: Barrett
authors.forename: Richard
authors.initials: R
authors.lastname: Harrington
authors.forename: Peter
authors.initials: P
authors.lastname: McGuffin
authors.forename: Michael
authors.initials: M
authors.lastname: Owen
authors.forename: William
authors.initials: W
authors.lastname: Ollier
authors.forename: Jane
authors.initials: J
authors.lastname: Worthington
authors.forename: Michael
authors.initials: M
authors.lastname: Gill
authors.forename: Aiveen
authors.initials: A
authors.lastname: Kirley
authors.forename: Ziarih
authors.initials: Z
authors.lastname: Hawi
authors.forename: Michael
authors.initials: M
authors.lastname: Fitzgerald
authors.forename: Philip
authors.initials: P
authors.lastname: Asherson
authors.forename: Sarah
authors.initials: S
authors.lastname: Curran
authors.forename: John
authors.initials: J
authors.lastname: Mill
authors.forename: Alison
authors.initials: A
authors.lastname: Gould
authors.forename: Eric
authors.initials: E
authors.lastname: Taylor
authors.forename: Lyndsey
authors.initials: L
authors.lastname: Kent
authors.forename: Nick
authors.initials: N
authors.lastname: Craddock
authors.forename: Anita
authors.initials: A
authors.lastname: Thapar
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000235:genetics* / Q000523:psychology; D002648:Child; D019955:Conduct Disorder / Q000150:complications / Q000235:genetics* / Q000523:psychology; D004247:DNA / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D018598:Minisatellite Repeats / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4
chemical_list: C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4; D004247:DNA