Atieh Alizadenik - department of biology ,Damghan branch,Islamic Azad university,Damghan,Iran
Ali Shahbazi - department of biology ,Damghan branch,Islamic Azad university,Damghan,Iran
Arvin Haghighatfard - Department of biology, Tehran North branch, Islamic Azad University, Tehran, Iran
Sahel Hemmati - Pediatric neurorehabilitation research center, University of social welfare and rehabilitation sciences, Tehran, Iran

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopment behavioral disorder in children with no clarified etiology. ADHD is a disease with high heritability and major genetic bases. Gene expression studies could help to better understand the mechanisms and pathways involved in the disorder as well as development of molecular diagnosis markers. In present study associations between three single nucleotide polymorphisms in dopaminergic pathway with ADHD were assessed. Three SNPs were presented in D2 receptor of dopamine (DRD2), dopamine beta hydroxylase (DBH) and Catechol-O-Methyltransferase (COMT) genes.Blood samples were collected from 150 Iranian ADHD patients and 250 non-psychiatric subjects. DNA was extracted from blood samples and ARMS-PCR was used for evaluation the frequency of three SNPs, rs4680 in COMT, rs1800497 in DRD2 and rs1611115 in DBH, in ADHD patient vs. non-psychiatric children.Results have been showed that all three SNPs were significantly associated with ADHD.Findings of present study confirmed association of these SNPs with ADHD in Iranian population. Also support the dopaminergic hypothesis about etiology of ADHD. It seems that rs4680 in COMT, rs1800497 in DRD2 and rs1611115 in DBH may use as prognostic marker for ADHD.

ADHD, COMT, DRD2, DBH