Attention-deficit/hyperactivity disorder (ADHD) association with the DAT1 core promoter −67 T allele

• Published in: Brain research Vol. 1101; no. 1; pp. 1 - 4
• Main Authors: Ohadi, Mina, Shirazi, Elham, Tehranidoosti, Mehdi, Moghimi, Narges, Keikhaee, Mohammad R., Ehssani, Sima, Aghajani, Ali, Najmabadi, Hossein
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 26.07.2006; Amsterdam Elsevier; New York, NY
• Subjects: ADHD; Adolescent; Association; Attention Deficit Disorder with Hyperactivity - genetics; Attention deficit disorders. Hyperactivity; Biological and medical sciences; Case-Control Studies; Child; Child clinical studies; Child, Preschool; DAT1; Dopamine Plasma Membrane Transport Proteins - genetics; Female; Gene Frequency; Humans; Linkage Disequilibrium; Male; Medical sciences; Minisatellite Repeats; Polymorphism; Polymorphism, Genetic - genetics; Promoter; Promoter Regions, Genetic - genetics; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Promoter; ADHD; Association; DAT1; Polymorphism; Human; Dopamine; Hyperactivity; Catecholamine; Attentional disorder; Gene; Neurotransmitter; Attention disorder with hyperactivity; Carrier protein
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2006.05.024

Association between attention deficit hyperactivity disorder (ADHD) and the 10-repeat allele of a polymorphism (a 40 bp variable number of tandem repeats) in the dopamine transporter gene (DAT1) has been reported by several groups. In this study, we examined whether either allele of the DAT1 core promoter −67 functional polymorphism is associated with ADHD in a case/control study. The allele and genotype frequencies of the polymorphism were studied in 110 patients and 120 controls, which were matched on the basis of sex, age and ethnicity. The genotype frequencies in the patients group were as follows: AA 19.2%; AT 65.2%; TT 15.4% vs. the genotype frequencies in the control group: AA 47.5%; AT 43.3%; TT 9.2% [ χ 2 = 20.73, df = 2, P ≤ 0.0001]. The T allele of the −67A/T polymorphism revealed an ∼1.56-fold excess in the patients group comparing with the controls [ χ 2 = 14.50, df = 1 ( P ≤ 0.001). For the first time, these findings provide tentative evidence of the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of ADHD at least in the Iranian population that we have studied. Further work is warranted to confirm this finding and to assess its generalization to other ethnic groups.