Serotonin Transporter Gene Polymorphism in Patients with Schizophrenic Disorders

Abstract

Objective: Studies performed to solve the genetic basis of schizophrenia have focused on the role of serotonin in the etiology of schizophrenia and the function of serotonin transporter gene. This study aimed to investigate whether there was a relationship between schizophrenia and polymorphism of the Variable Number of Tandem Repeats (VTNR) and 5-HTT Gene-Linked Polymorphic Region (5-HTTLPR) variants in the transcriptional control region of the serotonin transporter gene or not.Method: A total of 55 schizophrenia patients who were diagnosed according to the diagnostic criteria of DSM-IV-TR and 32 healthy volunteers (the control group) were included in the study. DNAs were extracted from the bloods collected from the patient and control groups with the salting-out method. Alleles of the serotonin transporter gene polymorphism were determined with the polymerase chain reaction (PCR) method.Results: Based on the serotonin transporter gene intron 2 VNTR polymorphism, the distribution of 12/12, 12/10, 10/10, and 12/9 genotypes was 47.3%, 47.3%, 3.6%, and 1.8% in the patients and 46.9%, 46.9% and 6.3% respectively in the control group. There was no 12/9 genotype in the control group. The distribution of L/L, L/S and S/S genotypes according to the 5-HTTLPR polymorphism was 30.9%, 41.8% and 27.3% in the patients and 28.1%, 50.0% and 21.9% respectively in the control group. Conclusion: Although the allele and genotype distributions of the serotonin transporter gene polymorphism relatively differed between the patient and control groups this difference was not statistically significant.