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Intelligence in DSM‐IV combined type attention‐deficit/hyperactivity disorder is not predicted by either dopamine receptor/transporter genes or other previously identified risk alleles for attention‐deficit/hyperactivity disorder
Author(s) -
SonugaBarke Edmund J.S.,
Brookes KeeleyJoanne,
Buitelaar Jan,
Anney Richard,
Bitsakou Paraskevi,
Baeyens Dieter,
Buschgens Cathelijne,
Chen Wai,
Christiansen Hanna,
Eisenberg Jacques,
Kuntsi Jonna,
Manor Iris,
Meliá Amanda,
Mulligan Aisling,
Rommelse Nanda,
Müller Ueli C.,
Uebel Henrik,
Banaschewski Tobias,
Ebstein Richard,
Franke Barbara,
Gill Michael,
Miranda Ana,
Oades Robert D.,
Roeyers Herbert,
Rothenberger Aribert,
Sergeant Joseph,
Steinhausen Hans Christoph,
Thompson Margaret,
Taylor Eric,
Asherson Philip,
Faraone Stephen V.
Publication year - 2007
Publication title -
american journal of medical genetics part b: neuropsychiatric genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.393
H-Index - 126
eISSN - 1552-485X
pISSN - 1552-4841
DOI - 10.1002/ajmg.b.30596
Subject(s) - attention deficit hyperactivity disorder , dopamine transporter , allele , proband , psychology , psychiatry , conduct disorder , genetics , dopamine , dopaminergic , biology , gene , neuroscience , mutation
A major goal of genetic studies of attention deficit hyperactivity disorder (ADHD) is to identify individual characteristics that might help segregate the disorder's inherent heterogeneity. [Mill et al. (2006); Arch Ger Psychiatry 63:462–469] recently reported a potentially important association between two dopamine‐related risk polymorphisms (DRD4 variable number tandem repeat (VNTR) in exon 3 and DAT1 VNTR in the 3′ UTR) and lowered IQ in ADHD. The objective of the current study was to replicate the [Mill et al. (2006); Arch Ger Psychiatry 63:462–469] findings in a clinical sample and to extend the analysis to a large range of alternative SNP markers of putative ADHD risk alleles identified in a recent study [Brookes et al. (2006); Mol Genet 11:934–953]. Participants were 1081 children and adolescents with a research‐confirmed combined type ADHD diagnosis and 1300 unaffected siblings who took part in the International Multi‐centre ADHD Genetics (IMAGE) project. They were recruited from multiple settings from across Europe: Belgium, Britain, Germany, Ireland, Israel, Netherlands, Spain and Switzerland. The results were that ADHD was associated with reduced IQ. However, there was no association between the two dopamine‐related risk polymorphisms and IQ in either the probands or their siblings. Furthermore, other selected genetic markers previously demonstrated to be associated with ADHD in this sample were not associated with IQ. This large scale study with a clinically ascertained and regorously diagnosed sample failed to replicate the association between genetic polymorphisms in the dopamine system and IQ in ADHD. We also observed no association of other SNPs with IQ in ADHD. © 2007 Wiley‐Liss, Inc.