Polymorphism of Dopamine D2-141C Ins/Del Receptor Gene in Paranoid Schizophrenia and Non Schizophrenia Patients of Batak Ethnicity in Sumatera Utara

Abstract

Introduction: Schizophrenia is a chronic mental condition which is characterized by reality distortion as well as thought, speech and behavior disorders. Several factors that may cause schizophrenia include genetic abnormalities of dopamine receptors that contribute to disorders in function of the brain, several studies have found an association between schizophrenic and non schizophrenic patients in the dopamine receptor gene polymorphism D2 -141C Ins/Del.

Aim: To investigate the relationship of DRD2 -141C Ins/Del gene polymorphism in schizophrenic and non-schizophrenic patients of Batak ethnicity in Sumatera Utara, Indonesia.

Methods: This research was done as an unpaired analytical case-control study. The subjects of the study were DNA isolates obtained from 60 patients of paranoid schizophrenia and 54 non-schizophrenia of Batak ethnicity in Sumatera Utara, Indonesia. PCR examination was performed on the DNA isolates to examine D2 -141C Ins/Del dopamine receptor gene polymorphism. The data collected were then analyzed statistically.

Result: In this study, three variants of DRD2 gene polymorphism (I/D: 304bp, 160bp, 144bp), (I/I: 160bp, 144bp), (D/D: 304bp) was identified. In both schizophrenic and non-schizophrenic patients, the highest I/D genotypes were identified (71.7%) and (63%) , and the least D/D genotypes were identified (6.7%) and (7.4%) with p = 0.726. Based on the allele distribution there was no difference of risk on allele D and allele I on the cause factor of schizophrenia (OR: 1.13; 95% CI: 0.66-1.92). According to Hardy-Weinberg Equilibrium law, both schizophrenic and non schizophrenic patients of Batak ethnicity in Sumatera Utara is in disequilibrium p = 0.0002 and p = 0.0057 with significance of p <0,05.

Conclusion: There is no significant association between genotypic distribution and DRD2 -141C Ins/Del gene alleles in schizophrenic and non schizophrenic patients.