Molecular Analysis of 5-HTTLPR variants of SLC6A4 gene in children and adolescents with ADHD in North West of Iran

Abstract

Attention Deficit Hyperactivity Disorder is a consistent pattern of inattention, hyperactivity, and impulsivity behaviors, and is one of the most common psychiatric disorders in children and adolescents that encompasses all aspects of a person's life. The rate of ADHD heritability has been reported in different studies ranging from 60 to 80%. The involvement of systems related to the serotonergic function of the nervous system in ADHD has been repeated in many studies. However, studies differ in explaining the importance and details of the pathways involved whether at the gene level or the level of the brain regions involved. Based on these differences in the results and the increasing awareness of families about this disorder and the lack of regional studies on this issue, we decided to study the incidence of SCL6A4 gene in the case and control groups in the Turkish population. Method: The present study was designed as a case-control study to investigate the polymorphism of the 5HTTLPR promoter region of the SCL6A4 gene. The patient group consisted of 77 children with ADHD less than 12 years of age and the control group of children less than 12 years of age without any psychiatric disorders. . Two alleles of the 5HTTLPR polymorphism known as the L allele and the S allele were examined in two study arms. Results: A total of 77 children with a diagnosis of ADHD and 100 children were included as the control group. Of these, 84 percent were boys and 16 percent were girls. The mean age of the study population was 8.7 years (± 2.5 years). The most abundant genotype was LS, accounting for 41% of the total. Comparison of genotypes between the case and control groups had a P-value of 0.71, meaning that there was no significant difference between the two groups in the genotype of 5-HTTLPR polymorphism.