Genetic Findings In Attention Deficit Hyperactivity Disorder

January 22, 1998

In their studies of attention deficit hyperactivity disorder (ADHD) investigators at the University of California, Irvine and University of Toronto, Canada, confirmed and extended previous observations implicating alterations in the dopamine D4 receptor (DRD4) in ADHD. In a population association (case-control) study of 39 children with a refined phenotype of ADHD and 39 ethnically matched controls, the researchers observed an increased percentage of the 7 repeat allele of DRD4 (29% vs 12%) and the 7+ genotype (49% vs 21%) in the ADHD group compared to the control group. In a replication and extension of their initial study, they recruited another group of ADHD children (7-12 years old) and found percentages of the 7 repeat allele (28%) and the 7+ genotype (48%) consistent with their previous findings. A family-based approach was used to evaluate a predicted association of DRD4 and ADHD based on a test of allele transmission focused on the 7 repeat allele. They identified 52 families based on the diagnosis of the refined phenotype of ADHD in the children and the availability of genetic material from both biological parents as well as from the affected children. Haplotype relative risk (HRR) analysis was performed to test our a priori hypothesis and produced significant positive results. This provides additional evidence that the DRD4 gene is associated with a refined phenotype of attention deficit hyperactivity disorder. This work is published in the January 1988 issue of Molecular Psychiatry.

For information on this Molecular Psychiatry article, please contact the author:
Dr. James M. Swanson , The Child Development Center, Department of Pediatrics,
University of California, Irvine, USA; phone: 714-824-1824; FAX: 714-824-1811;

This article is from the January 1988 issue of Molecular Psychiatry, an independent peer-reviewed journal published by Stockton Press/Macmillan Press.

Editor: Julio Licinio, MD - editorial assistant: Julie Vianello Bldg. 10/2D46, 10 Center Drive, Bethesda, MD 20892-1284, USA phone: +1 301 496-6979; FAX: +1 301 402-1561 e-mail:

Publisher: Marija Vukovojac, Stockton Press, phone and FAX: +44 1483 892119;
e-mail: 100743.2265@CompuServe.COM

For information on the scientific aspects of the article please contact the authors. Pre-prints of the articles can be obtained from Ms. Julie Vianello: phone: +1 301 496-6979; FAX: +1 301 402-1561; e-mail:

Molecular Psychiatry

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