title: Associations between serotonin transporter gene (SLC6A4) methylation and clinical characteristics and cortical thickness in children with ADHD.
abstract: BACKGROUND
  Attention deficit hyperactivity disorder (ADHD) is a common, highly heritable psychiatric disorder. Additionally, environmental factors such as perinatal stress and early adversities contribute to the occurrence and severity of ADHD. Recently, DNA methylation has emerged as a mechanism that potentially mediates gene-environmental interaction effects in the aetiology and phenomenology of psychiatric disorders. Here, we investigated whether serotonin transporter gene (SLC6A4) methylation patterns were associated with clinical characteristics and regional cortical thickness in children with ADHD.
  
  
  METHODS
  In 102 children with ADHD (age 6-15 years), the methylation status of the SLC6A4 promoter was measured. Brain magnetic resonance imaging was obtained and ADHD symptoms were evaluated.
  
  
  RESULTS
  A higher methylation status of the SLC6A4 promoter was significantly associated with worse clinical presentations (more hyperactive-impulsive symptoms and more commission errors). Additionally, a negative correlation was observed between SLC6A4 methylation levels and cortical thickness values in the right occipito-temporal regions.
  
  
  CONCLUSIONS
  Our results suggest that the SLC6A4 methylation status may be associated with certain symptoms of ADHD, such as behavioural disinhibition, and related brain changes. Future studies that use a larger sample size and a control group are required to corroborate these results.
authors.affiliation: Department of Psychiatry,Seoul National Hospital,Seoul,Republic of Korea.
authors.forename: S
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Biomedical Engineering,Hanyang University,Seoul,Republic of Korea.
authors.forename: J-M
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Division of Child and Adolescent Psychiatry,Department of Psychiatry,Seoul National University College of Medicine,Seoul,Republic of Korea.
authors.forename: J-W
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Lab Genomics Clinical Research Institute,Seoul,Republic of Korea.
authors.forename: D-Y
authors.initials: DY
authors.lastname: Cho
authors.affiliation: Department of Biomedical Engineering,Hanyang University,Seoul,Republic of Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Yun
authors.affiliation: Department of Psychiatry,College of Medicine,Chung Ang University,Seoul,Republic of Korea.
authors.forename: D H
authors.initials: DH
authors.lastname: Han
authors.affiliation: Uimyung Research Institute for Neuroscience,Sahmyook University,Seoul,Republic of Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Cheong
authors.affiliation: Division of Child and Adolescent Psychiatry,Department of Psychiatry,Seoul National University College of Medicine,Seoul,Republic of Korea.
authors.forename: B-N
authors.initials: BN
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D001921:Brain / Q000473:pathology*; D002648:Child; D019175:DNA Methylation; D005260:Female; D059647:Gene-Environment Interaction; D005838:Genotype; D006801:Humans; D006948:Hyperkinesis / Q000235:genetics*; D008279:Magnetic Resonance Imaging; D008297:Male; D011401:Promoter Regions, Genetic; D011569:Psychiatric Status Rating Scales; D056910:Republic of Korea; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: Attention deficit hyperactivity disorder; brain imaging; gene–environment interaction; neuropsychology