title: Association between alpha-2a-adrenergic receptor gene and ADHD inattentive type.
abstract: BACKGROUND
  Previous investigations have demonstrated that an MspI polymorphism at the adrenergic alpha2A receptor gene (ADRA2A) is associated with severity of attention-deficit/hyperactivity disorder (ADHD) inattentive symptoms in clinical samples composed mainly of subjects with ADHD, combined type. This study aimed to investigate the association between this ADRA2A polymorphism and attention-deficit/hyperactivity disorder-inattentive type (ADHD-I) in a nonreferred sample.
  
  
  METHODS
  In a case-control study, we assessed a sample of 100 children and adolescents with ADHD-I and 100 non-ADHD controls. Cases and controls were matched by gender and age and were screened by using teacher reports in a revised version of the Swanson, Nolan, and Pelham rating scale at 12 schools. Psychiatric diagnoses were derived through structured diagnostic interviews.
  
  
  RESULTS
  Homozygous subjects for the G allele at the ADRA2A had significantly higher odds ratio (OR) for ADHD-I than did those with other genotypes (CC + CG genotypes), even after adjusting for potential confounders (p = .02; OR = 3.78; 95% confidence interval = 1.23-11.62). In family-based analyses, no significant associations were detected.
  
  
  CONCLUSIONS
  Our results suggest that the ADRA2A may be associated with ADHD-I, replicating previous findings from clinical samples that have suggested the importance of this gene for the dimension of inattention. In addition, these results support the role of the noradrenergic system in ADHD.
authors.affiliation: ADHD Outpatient Clinic Child and Adolescent Psychiatric Division, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos 2350, Porto Alegre, Rio Grande do Sul 90035-003, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Schmitz
authors.forename: Daniel
authors.initials: D
authors.lastname: Denardin
authors.forename: Tatiana Laufer
authors.initials: TL
authors.lastname: Silva
authors.forename: Thiago
authors.initials: T
authors.lastname: Pianca
authors.forename: Tatiana
authors.initials: T
authors.lastname: Roman
authors.forename: Mara Helena
authors.initials: MH
authors.lastname: Hutz
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Faraone
authors.forename: Luis Augusto
authors.initials: LA
authors.lastname: Rohde
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D011569:Psychiatric Status Rating Scales; D018341:Receptors, Adrenergic, alpha-2 / Q000235:genetics*; D012720:Severity of Illness Index
chemical_list: C547768:ADRA2A protein, human; D018341:Receptors, Adrenergic, alpha-2