title: Family-based association study of serotonin transporter gene polymorphisms in attention deficit hyperactivity disorder: no evidence for association in UK and Taiwanese samples.
abstract: Five independent studies have reported associations between serotonin transporter gene (5-HTT) polymorphisms and attention deficit hyperactivity disorder (ADHD). Four studies found evidence for association between the long-allele of a 44-base pair insertion/deletion polymorphism (5-HTTLPR), one of the studies found association to a variable number tandem repeat within intron 2, another to the T-allele of a single base pair substitution in the 3'-untranslated regions and another reported preferential transmission of a haplotype of the three markers (long-allele/10-repeat-allele/T-allele). One further study found no evidence for these associations. We investigated the association of these three markers in two samples of ADHD patients from the United Kingdom (n = 197) and Taiwan (n = 212), using within-family tests of association. No association was found between any of the three markers in either of the two populations. Although we found some evidence for the preferential transmission of a rare haplotype (long-allele/9-repeat-allele/T-allele; chi2 = 4.5, P = 0.034), we concluded that this most likely occurred by chance factors alone.
authors.affiliation: MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College, London, United Kingdom.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.forename: Jonathan
authors.initials: J
authors.lastname: Mill
authors.forename: Chi-Ken
authors.initials: CK
authors.lastname: Chen
authors.forename: Keeley
authors.initials: K
authors.lastname: Brookes
authors.forename: Eric
authors.initials: E
authors.lastname: Taylor
authors.forename: Philip
authors.initials: P
authors.lastname: Asherson
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D013624:Taiwan; D006113:United Kingdom
chemical_list: D050486:Serotonin Plasma Membrane Transport Proteins