Candidate Gene Expression Investigation in Children With Attention Deficit Hyperactivity Disorder

Abstract

Background: In this study, expression level analysis of genes associated with Attention Deficit Hyperactivity Disorder (ADHD) (SLC6A3, SLC6A4, SLC1A2, VMAT2, MAOA, COMT, GLYAT, GRM5, DRD4, TPH1, and ADRA2C) by pre-treatment and post-treatment with Atomoxetine and Methylphenidate was investigated. Methods: Forty-three ADHD diagnosed children and 38 healthy children were included to study. Forty-three patients with ADHD were divided into two groups, of which 35 patients used methylphenidate and 8 patients use atomoxetine. Five main study groups were generated: A control group, a group that includes methylphenidate pre-treatment samples, a group includes methylphenidate post-treatment samples, a group that includes atomoxetine pre-treatment samples and a group that includes atomoxetine post-treatment samples. Blood samples (10 ml each) were taken from everyone in study groups into EDTA tubes and RNA isolation was performed. mRNA expression levels of 11 determined candidate genes were showed via reverse transcription quantitative PCR method. Results: The expression levels of SLC6A3 (DAT) of ADHD diagnosed children were significantly higher than the control group, while the mRNA expression levels of SLC6A4, SLC1A2, VMAT2, MAOA, COMT, GLYAT, and TPH1 genes were significantly lower (t- test, p≤0.01).Conclusion: The expression level differences of these genes were determined to be useful as biomarkers in the diagnosis of ADHD. More patient numbers and studies with different groups are needed to fully reveal the relationship between these genes and the disease and its treatment.