Association Study Between Schizophrenia And Catechol-O-methyltransferase Gene Polymorphism

Objective: To investigate the relationship between Catechol-O-methyltransfer-ase(COMT) geneVal158Met polymorphism and schizophrenia in Chinese Han population of Kunming province. Method : A clinical evaluation of all schizophrenic patients was accomplished by the PANSS test and the Overt Aggression Scale was used to test the schizophrenic patients' aggression behavior. Schizophrenic patients were administered 9 neuropsychological tests: Arithmetic, Digital Symbol, Digital Span , Immediate Logical Memory, Delay Logical Memory, Immediate Vision Memory, Delay Vision Memory, Bloke Design, Verbal Fluency Test, Trail Marking Test A and B. We also detected the Neuron Soft Sign.The Polymerase Chain Reaction-Restriction Fragment Length Polymorphisms technique was used to detect the genotypes of COMT gene in 88 patients with schizophrenia and 45 healthy controls. Result: (1) Regarding Val 158 Met COMT gene polymorphisms no statistically significant difference was found between schizophrenic patients.and control subjects. There was significant difference between female schizophrenic patients and control group'allele frequencies. (2) Significant COMT gene Val158Met polymorphism difference was found between Chinese Han population of Kunming province and Caucasians of Unitied Kingdom. (3) There was significant difference between male violent and nonviolent group'allele frequencies.(OR=4.55,95%CI: 1. 365-15. 191) (4) A significant COMT genotype effect was found: Val/Val individuals had the lowest Digit span Test (reverse recite) performance, Met/Met individuals had the highest performance. Conclusions: (1) There was significant COMT gene Vall58Met polymorphism difference between Chinese Han population of Kunming province and Caucasians of United Kingdom. (2) Female patients with at least one low activity associated COMT-A alleles showed a tendency of elevated risk for schizophrenia compare with those homozygous for the high activity associated COMT-G alleles. (3) The COMT gene polymorphism was associated with schizophrenic patients' aggressive behavior. The COMT-A alleles of male schizophrenicpatients was associated with aggressive behavior. (4) The COMT gene Val158Met polymorphism was associated with Digit span (reverse recite) Test performance. Val/Val individuals had the lowest Digit span (reverse recite) Test performance and Met/Met individuals had the highest. performance.The found suggest that the COMT gene polymorphism affect working memory and the physiology of the prefrontal cortex in schizophrenic patients, probably by affecting prefrontal dopamine signaling.