Table of Contents
International Scholarly Research Notices
Volume 2017 (2017), Article ID 2494537, 5 pages
Research Article

DRD4 Gene Polymorphisms as a Risk Factor for Children with Attention Deficit Hyperactivity Disorder in Iranian Population

1Department of Physiology, Tabriz Branch, Islamic Azad University, Tabriz, Iran
2Research Center of Psychiatry and Behavioral Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
3Department of Otolaryngology, Head and Neck Surgery, Tabriz University of Medical Sciences, Tabriz, Iran

Correspondence should be addressed to Shahrokh Amiri

Received 27 February 2017; Revised 13 April 2017; Accepted 23 April 2017; Published 24 May 2017

Academic Editor: Pieter J. Hoekstra

Copyright © 2017 Seyed Mahmoud Tabatabaei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background and Objective. Dopamine dysfunction is known to be associated with attention deficit hyperactivity disorder (ADHD). Dopamine D4 receptor gene (DRD4) is one of the important genes in this pathway. This study intended to investigate the variable number of tandem repeats (VNTR) in exon 3 of the DRD4 gene in Iranian children and adolescents. Materials and Methods. In this study, 130 children with ADHD, aged 6–14 years, and 130 healthy children, within the same age range, were enrolled. All children were selected from northwest of Iran which have Caucasian ethnic background and are of a Turkic ethnic group. VNTR polymorphisms of the DRD4 gene were evaluated by PCR using exon 3-specific primers followed by agarose gel electrophoresis. Findings. The Hardy-Weinberg principle and Chi-square test showed a significant difference in 4-repetition (4R) alleles between the ADHD (76.2%) and control (53.8%) groups (; ; ). The least percentage of repetition alleles in both groups was 2R. Conclusion. There is a significant correlation between the 4R alleles of DRD4 and ADHD in the northwest of Iran.