Étude statistique et génétique de la schizophrénie dans la région de Constantine.

Abstract

Introduction: schizophrenia is a complex psychiatric disorder with an etiology involving both environmental and genetic factors. Dopaminergic pathways, in particular, play a key role in its pathophysiology. Several dopamine-related genes, including DRD2, DBH, and ACE, are involved in modulating this pathway and may influence the risk of developing schizophrenia. This study aims to assess the association between three specific genetic polymorphisms in these genes (-141C Ins/Del of DRD2, I/D of DBH, and I/D of ACE) and schizophrenia, as well as to explore the sociodemographic and clinical profiles of affected patients. Patients and Methods: this case-control study includes schizophrenic patients and controls matched by age and sex. The -141C Ins/Del polymorphism of DRD2 was genotyped using PCR-RFLP with Sanger sequencing validation, while DBH and ACE polymorphisms were genotyped by PCR. Sociodemographic and clinical data were collected and statistically analyzed using SPSS version 26, with appropriate tests applied for qualitative and quantitative variables and genetic models to explore associations between the polymorphisms and schizophrenia. Results: the results show a significant association between the -141C Ins/Del polymorphism of DRD2 and schizophrenia (p=0.001), suggesting its involvement in genetic vulnerability to this disorder. In contrast, the I/D polymorphisms of DBH and ACE did not show any notable association with schizophrenia in our population. Sociodemographic analysis revealed a male predominance (sex ratio of 3.53), with most patients being single, unemployed, and having a medium education level. The average age of symptom onset was 24 years. A significant association was also observed between schizophrenia and tobacco use (p=0.0001), while no association was found with cannabis or other substance use. Conclusion: these findings highlight the importance of the -141C Ins/Del polymorphism of the DRD2 gene in susceptibility to schizophrenia and underscore the need for further studies to explore the role of this gene in the pathophysiology of this disorder, as well as the impact of environmental factors such as smoking. These results contribute to a better understanding of the genetic basis of schizophrenia and open avenues for future research, including further studies on diverse populations to validate and generalize these findings.