title: ADRA2A polymorphisms and ADHD in adults: possible mediating effect of personality.
abstract: Several studies have tested for the association between polymorphisms in the ADRA2A gene and childhood ADHD. A meta-analysis of these results, however, has pointed towards a significant heterogeneity, raising the need for explanatory studies. As the effect of other relevant clinical characteristics could be a possible source, we studied three polymorphisms in the ADRA2A gene (-1291 C>G-MspI or rs1800544; -262 G>A-HhaI or rs1800544; 1780 C>T-DraI or rs553668) in 403 adult patients with ADHD assessed in relation to comorbidity and personality characteristics, as well as in 232 controls. The diagnosis followed DSM-IV criteria, and personality dimensions were evaluated with the Temperament and Character Inventory (TCI). There were no significant differences in allele and genotype frequencies between cases and controls. Patients carrying the G allele of rs1800544 presented lower scores in harm avoidance, and carriers of the T allele of rs553668 had more novelty seeking and less harm avoidance and persistence. Additionally, the haplotype carrying the G-G-T alleles (rs1800544-rs1800545-rs553668) was associated with lower scores in harm avoidance and persistence, and higher scores in novelty seeking compared to other haplotypes. These findings suggest that the conflicting findings obtained in association studies between ADRA2A polymorphisms and ADHD might be related to temperament profiles, and support additional studies addressing these effects in larger samples.
authors.affiliation: Department of Genetics, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Caio Cesar Silva
authors.initials: CC
authors.lastname: de Cerqueira
authors.forename: Evelise Regina
authors.initials: ER
authors.lastname: Polina
authors.forename: Verônica
authors.initials: V
authors.lastname: Contini
authors.forename: Francine Zanquetta Coelho
authors.initials: FZ
authors.lastname: Marques
authors.forename: Eugenio Horacio
authors.initials: EH
authors.lastname: Grevet
authors.forename: Carlos Alberto Iglesias
authors.initials: CA
authors.lastname: Salgado
authors.forename: Paula Oliveira Guimarães
authors.initials: PO
authors.lastname: da Silva
authors.forename: Felipe Almeida
authors.initials: FA
authors.lastname: Picon
authors.forename: Paulo
authors.initials: P
authors.lastname: Belmonte-de-Abreu
authors.forename: Claiton Henrique Dotto
authors.initials: CH
authors.lastname: Bau
mesh_terms: D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D016009:Chi-Square Distribution; D055106:Genome-Wide Association Study; D006801:Humans; D010551:Personality / Q000235:genetics*; D010554:Personality Disorders / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D010555:Personality Inventory; D011110:Polymorphism, Genetic / Q000235:genetics*; D011569:Psychiatric Status Rating Scales; D018341:Receptors, Adrenergic, alpha-2 / Q000235:genetics*
chemical_list: C547768:ADRA2A protein, human; D018341:Receptors, Adrenergic, alpha-2