Attention-deficit hyperactivity disorder: A study of association with both the dopamine transporter gene and the dopamine D4 receptor gene
Article first published online: 29 MAY 2001
Copyright © 2001 Wiley-Liss, Inc.
American Journal of Medical Genetics
Volume 105, Issue 5, pages 471–478, 8 July 2001
How to Cite
Roman, T., Schmitz, M., Polanczyk, G., Eizirik, M., Rohde, L. A. and Hutz, M. H. (2001), Attention-deficit hyperactivity disorder: A study of association with both the dopamine transporter gene and the dopamine D4 receptor gene. Am. J. Med. Genet., 105: 471–478. doi: 10.1002/ajmg.1408
- Issue published online: 23 OCT 2002
- Article first published online: 29 MAY 2001
- Manuscript Accepted: 29 MAR 2001
- Manuscript Received: 12 DEC 2000
- Programa de Apoio a Núcleos de Excelência, Financiadora de Estudos e Projetos, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, and Fundo de Incentivo à Pesquisa e Eventos, Hospital de Clínicas de Porto Alegre
Attention-deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders of childhood. The role of genetic factors in its etiology is strongly supported by family, adoption, and twin studies. Several investigations have reported associations between ADHD and both the 7-repeat allele of the 48 bp VNTR at the DRD4 gene and the 10-repeat allele of the 40 bp VNTR at the DAT1 gene, but the results have been inconsistent. A sample of 81 Brazilian ADHD children and adolescents and their parents were screened for these DRD4 and DAT1 VNTRs. An excess of the DRD4 7-repeat allele was observed when both ADHD probands and their parents were compared with an ethnically matched control sample (chi-square = 11.55, P = 0.03; chi-square = 12.17, P = 0.03, respectively). However, haplotype relative risk (HRR) analysis showed no preferential transmission of the DRD4 7-repeat allele. No evidence of association with the DAT1 polymorphism was detected by both approaches. Nevertheless, an interaction effect of both genes on ADHD hyperactive/impulsive dimension was observed (F = 4.68; P = 0.03). These results add to the group of studies that together suggest a small effect of these genes in the susceptibility to ADHD. © 2001 Wiley-Liss, Inc.