Detection of DRD2 SER311CYS Variant in Schizophrenic Patients

The molecular pathogenesis of the schizophrenia has been extensively studied. The dopamine hypothesis is well-known possible mechanism in the etiology of schizophrenia and dopamine D2 receptor gene(DRD2 gene), one of the dopamine receptor genes, is believed to be a candidate gene for schizophrenia because D2 receptor has high affinity for the antipsychotic drugs. Some researchers have been studied for the variant of the DRD2 gene(Ser311→Cys) and suggest positive association of this polymorphism and schizophrenia in Japanese schizophrenic patients. However, following studies did not support that results. So the author investigated polymorphism of the dopamine D2 receptor gene(Ser3l1→Cys311) in a total of 42 schizophrenic patients and 50 controls.

To compare the Cys variant status between the schizophrenic patients and control group and to investigate the allelic pattern of DRD2 gene, PCR(polymerase chain reaction) and MASA((Mutated Allele Specific Amplification) were performed in 42 cases of schizophrenic patients' and 50 normal controls' whole blood. Schizophrenic patients clinical characteristics, family history of mental illness and response to therapy were examined.

The following results were summarized. 1) The detection of homozygote for Cys allele and heterozygote of Ser/Cys was one and one case in 42 schizophrenic patients, respectively. 2) None with Cys allele or any heterozygote was detected among 50 control groups. 3) So frequencies of Cys311 among 42 schizophrenics were three(3.6%). but there is no statistical significance. 4) There is no correlations between clinical characteristics of schizophrenic patients and Cys alleles.

There is no statistical difference in allele frequency of DRD2 Cys311 variant between schizophrenia and control groups. So this result was in line with the previous studies which did not show evidence of association between schizophrenia and D_2 receptor polymorphism(Ser311→Cys 311).