Association between DRD4 rs1800955 polymorphism and Attention Deficit Hyperactivity Disorder susceptibility among children from Northwest of Iran: a case-control study

Background: Attention deficit hyperactivity disorder (ADHD) is the most common and highly heritable psychiatric disorder among children which affects 3-7% of them all around the world. ADHD characterized by some symptoms such as extreme and inappropriate levels of motor activity, impulsivity and inattentiveness. Several studies have reported the association between dopaminergic pathway and ADHD. Dopamine D4 receptor gene and its variants is one of the major candidates that have been studied for ADHD. Here we investigated the genetic association between DRD4 rs1800955 polymorphism and ADHD among children from Northwest of Iran. Methods: This case-control study includes 200 ADHD children and 157 controls aged 6-12 years. ADHD children were diagnosed according to DSM-IV and Conners scale and were genotyped by PCR-Restriction fragment length polymorphism (RFLP) technique. Results: Frequencies of genotypes CC, TT and CT were 48 (24%), 15 (7.5%) and 137 (68.5%) in patient group and 50 (31.85% %), 7 (4.46%) and 100 (63.69 %) in control group respectively. According to results, there was no significant association between case and control groups (p>0.05). Conclusion: The results of this study indicate that there is no significant association between DRD4 rs1800955 polymorphism and attention deficit hyperactivity disorder among children from Northwest of Iran.