No evidence of association between a polymorphism in the COMT gene and clinical phenotypes of schizophrenia in China

Abstract

Catechol-O-methyl-transferase (COMT), which is involved in the metabolism of catecholamines, has been implicated in the pathogenesis of schizophrenia. Genetic polymorphism with a valine to methionine substitution at amino acid 158 leading to low-activity variant of the enzyme has been found to be associated with schizophrenia and violent behavior. However, negative findings have also been reported. We conducted a case-control study of the val158met polymorphism of the COMT gene to investigate the possible association with schizophrenia and clinical phenotypes in Chinese. Two hundred and six unrelated schizophrenic patients and 286 unrelated healthy controls of Han Chinese descent in Hong Kong were compared for genotype and allele frequencies of COMT polymorphisms by PCR amplification and restriction analysis. No evidence of association was detected at the diagnostic level and various clinical phenotypes including frontal lobe function, clinical symptoms, treatment response, suicide and violent behavior. Our data suggest that val158met polymorphism of COMT gene is not associated with schizophrenia at least at the diagnostic level. In view of our modest sample size and the low frequency of homozygous met158 genotype in the Chinese population, further large scale studies with detailed characterization of endophenotypes are essential for mapping this gene to schizophrenia and the associated traits.