title: Further evidence for the association between attention-deficit/hyperactivity disorder and the dopamine-beta-hydroxylase gene.
abstract: Attention-deficit/hyperactivity disorder (ADHD) is a very common and heterogeneous psychiatric disorder of childhood with marked inattentive, hyperactive, and impulsive symptoms. The DBH gene, the locus that encodes the enzyme dopamine-beta-hydroxylase (DbetaH), seems to be an important candidate gene for association studies, since DbetaH catalyzes the conversion of dopamine to norepinephrine. The aim of this study was to test for association between the DBH gene and ADHD in a sample of 88 Brazilian nuclear families. Haplotype relative risk (HRR) analysis of the DBH TaqI restriction site polymorphism showed a preferential transmission of the TaqI A2 allele in our whole ADHD sample (chi(2)=3.61, one-tailed P=0.03). The significant effect of the A2 allele was stronger when only families with no ADHD parental diagnosis were considered (chi(2)=5.42, one-tailed P=0.01). Our results suggest a contribution of this gene to ADHD susceptibility, partially replicating previous findings that have demonstrated an association between the DBH TaqI A2 allele and ADHD.
authors.affiliation: Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil. tatiana.roman@ufrgs.br
authors.forename: Tatiana
authors.initials: T
authors.lastname: Roman
authors.forename: Marcelo
authors.initials: M
authors.lastname: Schmitz
authors.forename: Guilherme V
authors.initials: GV
authors.lastname: Polanczyk
authors.forename: Mariana
authors.initials: M
authors.lastname: Eizirik
authors.forename: Luis A
authors.initials: LA
authors.lastname: Rohde
authors.forename: Mara H
authors.initials: MH
authors.lastname: Hutz
mesh_terms: D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000201:enzymology / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D004299:Dopamine beta-Hydroxylase / Q000235:genetics*; D005192:Family Health; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D009679:Nuclear Family; D011110:Polymorphism, Genetic
chemical_list: D004247:DNA; D004299:Dopamine beta-Hydroxylase; D015252:Deoxyribonucleases, Type II Site-Specific; C027046:TCGA-specific type II deoxyribonucleases