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Replication of a rare protective allele in the noradrenaline transporter gene and ADHD
Author(s) -
Xu X.,
Hawi Z.,
Brookes K.J.,
Anney R.,
Bellgrove M.,
Franke B.,
Barry E.,
Chen W.,
Kuntsi J.,
Banaschewski T.,
Buitelaar J.,
Ebstein R.,
Fitzgerald M.,
Miranda A.,
Oades R.D.,
Roeyers H.,
Rothenberger A.,
Sergeant J.,
SonugaBarke E.,
Steinhausen H.C.,
Faraone S.V.,
Gill M.,
Asherson P.
Publication year - 2008
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.30872
Subject(s) - single nucleotide polymorphism , snp , allele , odds ratio , norepinephrine transporter , genetics , attention deficit hyperactivity disorder , genotype , biology , gene , genetic association , allele frequency , replication (statistics) , medicine , transporter , psychiatry , virology
Replication is a key to resolving whether a reported genetic association represents a false positive finding or an actual genetic risk factor. In a previous study screening 51 candidate genes for association with ADHD in a multi‐centre European sample (the IMAGE project), two single nucleotide polymorphisms (SNPs) within the norepinephrine transporter ( SLC6A2 ) gene were found to be associated with attention deficit hyperactivity disorder (ADHD). The same SNP alleles were also reported to be associated with ADHD in a separate study from the Massachusetts General Hospital in the US. Using two independent samples of ADHD DSM‐IV combined subtype trios we attempted to replicate the reported associations with SNPs rs11568324 and rs3785143 in SLC6A2 . Significant association of the two markers was not observed in the two independent replication samples. However, across all four datasets the overall evidence of association with ADHD was significant (for SNP rs11568324 P = 0.0001; average odds ratio = 0.33; for SNP rs3785143 P = 0.008; average odds ratio = 1.3). The data were consistent for rs11568324, suggesting the existence of a rare allele conferring protection for ADHD within the SLC6A2 gene. Further investigations should focus on identifying the mechanisms underlying the protective effect. © 2008 Wiley‐Liss, Inc.