Molecular Analysis of STin2 (Intron 2) Variant of The SLC6A4 Gene in Children and Adolescents With Attention Deficit Hyperactivity Disorder

Abstract Background Attention deficit hyperactivity disorder (ADHD) is recognized as one of the most familiar childhood psychiatric disorders. Many molecular genetic reviews suggest that genes play a crucial role in susceptibility to ADHD. The serotonin transporter gene (SLC6A4) has polymorphisms that seem to correlate with ADHD development. The association between ADHD and the SLC6A4 gene variants in the Iranian population has not been investigated yet. This study analyzes the STin2 (intron 2) variant of the SLC6A4 gene in Iranian children and adolescents with ADHD . Materials and Methods In this retrospective case-control study, 86 ADHD patients and 99 healthy volunteers aged 5 to 14 years old were enrolled as the case group and the control group, respectively. The STin2 (intron2) fragment of the SLC6A4 gene was amplified using specific primers by conventional PCR, and three STin2 alleles of the SLC6A4 gene (STin2.9, STin2.10, and STin2.12) were examined using the acrylamide gel method. Results We found no significant difference between the ADHD and the control groups in STin2.9(34.9% vs 39.4%, p-value = 0.824), STin2.10(29.1% vs 23.2%, p-value = 1.354), and STin2.12(36% vs 36.4%, p-value = 0.986) variants. Conclusion It is concluded that there was no association between the frequency of STin2 variant alleles of the SLC6A4 gene andADHD, but in the study of risk estimation, it was found that allele 10 of this variant is a risk allele in ADHD patients.