Evaluation of several micro RNA (miRNA) levels in children and adolescents with attention deficit hyperactivity disorder

• miRNA 18a-5p, 22-3p, 24-3p, 106b-5p and 107 levels were decreased in ADHD.
• miRNA 155a-5p levels were increased in ADHD.
• miR-107 may be a candidate biomarker for ADHD.
• Dysregulation of circulating miRNAs may affect ADHD etiology and treatment.

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent childhood disorders, although disorders etiology and pathogenesis remains unknown, several theories about ADHD development have been proposed and many researchers believe that it is caused by both genetic and environmental factors. In this study we evaluated miR18a-5p, miR22-3p, miR24-3p, miR106b-5p, miR107, miR125b-5p and miR155a-5p levels in child and adolescent ADHD patients. The research sample consisted a group of 52 ADHD patients, and 52 healthy volunteer controls. There was no significant difference in age and sex between the two groups (p > 0.05). miRNA 18a-5p, 22-3p, 24-3p, 106b-5p and 107 levels were statistically significantly decreased in ADHD patients(p < 0.05). miRNA 155a-5p levels were increased in patients group (p < 0.05). The positive predictive value (PPV) and negative predictive value of miR107 was estimated for the cutoff point of 0.4480. PPV was 70% and NPV was 86.5% for the taken cut off point. There could be a close relationship between levels of circulating miRNAs and ADHD. If we could understand how the signaling pathways arranged by miRNAs, impact on CNS development, function and pathology this can improve our knowledge about ADHD etiology and treatment.