title: Association study between the monoamine oxidase A gene and attention deficit hyperactivity disorder in Taiwanese samples.
abstract: BACKGROUND
  Attention deficit hyperactivity disorder (ADHD) is a common and highly heritable disorder of childhood characterized by inattention, hyperactivity and impulsivity. Molecular genetic and pharmacological studies suggest the involvement of the dopaminergic, serotonergic and noradrenergic neurotransmitter systems in the pathogenesis of ADHD. Monoamine oxidase A (MAO-A) encodes an enzyme that degrades biogenic amines, including neurotransmitters such as norepinephrine, dopamine and serotonin. In this study we examined a 30 bp promoter variable number tandem repeat (VNTR) and a functional G/T single nucleotide polymorphism (SNP) at position 941 in exon 8 (941G/T) of MAO-A for association with ADHD in a Taiwanese sample of 212 ADHD probands.
  
  
  METHODS
  Within-family transmission disequilibrium test (TDT) was used to analyse association of MAO-A polymorphisms with ADHD in a Taiwanese population.
  
  
  RESULTS
  A nominally significant association was found between the G-allele of 941G/T in MAO-A and ADHD (TDT: P = 0.034. OR = 1.57). Haplotype analysis identified increased transmission of a haplotype consisting of the 3-repeat allele of the promoter VNTR and the G-allele of the 941G/T SNP (P = 0.045) to ADHD cases which the strong association with the G-allele drove.
  
  
  CONCLUSIONS
  These findings suggest the importance of the 941G/T MAO-A polymorphism in the development of ADHD in the Taiwanese population. These results replicate previously published findings in a Caucasian sample.
authors.affiliation: MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK. x.xu@iop.kcl.ac.uk
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.forename: Keeley
authors.initials: K
authors.lastname: Brookes
authors.forename: Chih-Ken
authors.initials: CK
authors.lastname: Chen
authors.forename: Yu-Shu
authors.initials: YS
authors.lastname: Huang
authors.forename: Yu-Yu
authors.initials: YY
authors.lastname: Wu
authors.forename: Philip
authors.initials: P
authors.lastname: Asherson
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000208:ethnology* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008995:Monoamine Oxidase / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D013624:Taiwan / Q000208:ethnology; D020080:Tandem Repeat Sequences
chemical_list: D008995:Monoamine Oxidase