Investigation of serotonin transporter gene polymorphisms in psoriasis patients

"Investigation of serotonin transporter gene polymorphisms in psoriasis patients", Trakya University Institute of Health Sciences, Department of Biophysics, Master Thesis, Edirne, 2025. Background and Aim: Psoriasis is a chronic inflammatory disease mediated by the immune system with increased proliferation of keratinocytes. Although the exact cause is unknown, it is thought that a multifactorial structure such as infection, trauma and psychological stress plays a role in its pathophysiology. The aim of this study was to investigate the association of intron 2 VNTR polymorphisms in the SLC6A4 gene with the development and pathogenesis of psoriasis. Material and Methods: In this study, genotyping was performed using Polymerase Chain Reaction (PCR) method with venous blood samples obtained from 121 patients with psoriasis and 123 healthy controls. We compared the distribution of these genetic variants in psoriasis patients and healthy individuals and evaluated whether these polymorphisms are associated with the disease. Results: The genotype distributions in the patient and control groups were compared, and no statistically significant difference was found between the groups. A statistically significant association was detected between genotype and the presence of metabolic syndrome in patients with psoriasis. It was observed that individuals with the STin2.10/STin2.10 genotype had a notably lower than expected prevalence of metabolic syndrome. Conclusion: When comparing the intron 2 VNTR genotypes of the SLC6A4 gene between psoriasis patients and healthy controls, it was observed that the STin2.10/STin2.10 genotype was significantly less frequent than expected among psoriasis patients with metabolic syndrome. This suggests that the STin2.10/STin2.10 genotype may have a protective effect against metabolic syndrome. Furthermore, the STin2.9 genotype was observed only in the control group, indicating that individuals with this genotype may have a protective advantage against the disease. Notably, three individuals in the control group who were biologically related (a mother and her two children, one male and one female) all possessed the STin2.9 genotype. This observation suggests that the STin2.9 genotype may be inherited genetically. We believe that increasing the sample size in future studies could contribute valuable insights to this field of research. Keywords: Psoriasis, SLC6A4, intron 2 VNTR, Serotonin Financial Support: The present study was supported by the Research Fund of Trakya University. Proje No: 2025/74