Association of DRD4 in children with ADHD and comorbid conduct problems

Jane Holmes, Antony Payton, Jennifer Barrett, Richard Harrington, Peter McGuffin, Michael Owen, William Ollier, Jane Worthington, Michael Gill, Aiveen Kirley, Ziarih Hawi, Michael Fitzgerald, Philip Asherson, Sarah Curran, John Mill, Alison Gould, Eric Taylor, Lyndsey Kent, Nick Craddock, Anita Thapar

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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.

Original languageEnglish
Pages (from-to)150-153
Number of pages4
JournalAmerican Journal of Medical Genetics Part B: Neuropsychiatric Genetics
Issue number2
Publication statusPublished - 8 Mar 2002
Externally publishedYes


  • Attention deficit hyperactivity disorder
  • Conduct disorder
  • Dopamine
  • DRD4
  • Genetics

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