Possible Effect of Dysregulations in Dopamine Receptor Expression on Specific Learning Disorder: DRD1 and DRD2 Gene Expressions

Abstract

Specific Learning Disorder (SLD) refers to impairments in a number of simple functions, including listening, speaking, basic reading, comprehension, arithmetic, mathematical reasoning, and written expression. In recent years, biomolecules with significant structural and functional gene expression have played a crucial role in neurodevelopmental disorders. The dopamine receptor 1 (DRD1) gene encodes the DRD1 receptor. The dopamine receptor 2 gene encodes the DRD2 receptor. DRDs are highly expressed in the prefrontal cortex, which is responsible for movement, reward, reinforcement, memory, and learning. The aim of this study is to investigate the contribution of these biomolecules to the pathophysiology of the disease by examining the expression levels of the DRD1 and DRD2 genes, which belong to the dopamine gene family and play a significant role in sensory and motor skills, in individuals with SLD. This study involved blood samples from 38 children and adolescents aged 6-16 years diagnosed with SLD and a control group of 35 children and adolescents without any psychiatric disorders. RNA was isolated from these samples, and gene expression levels were analyzed using qPCR. The data were analyzed using the online analysis program Qiagen Gene Globe Data Analysis Center, and p-values and fold changes were determined. Comparison of the target genes with the reference gene (ACTB) revealed that while the DRD1 gene showed a 7.15-fold increase in the patient group, this result was not statistically significant (P=0.288). In contrast, the DRD2 gene exhibited a statistically significant 7.27-fold upregulation in individuals with SLD (P=0.001). In conclusion, these two genes, known to play a role in epigenetic processes, are considered potential therapeutic targets in SLD; however, further studies are needed to confirm this relationship.

Keywords

• DRD1
• DRD2
• Gene expression
• qPCR

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