The Role of a Catechol-O-Methyltransferase (COMT) Val158Met Genetic Polymorphism in Schizophrenia: A Systematic Review and Updated Meta-analysis on 32,816 Subjects.

An association between a catechol-O-methyltransferase (COMT) Val156Met (rs4680) polymorphism and schizophrenia has been reported in the literature, although no conclusive outcomes have been attained. The aim of this study was to evaluate the association of the COMT Val108/158Met polymorphism with schizophrenia in a systematic review and meta-analysis. We performed a keyword search on PubMed and EBSCO databases. All English language case-control studies published up to April 2015 were selected. A total of 67 studies were selected for inclusion. The genotype distribution of subjects with schizophrenia was compared with healthy control subjects, using allelic, additive, dominant and recessive models. The pooled results from the meta-analysis (15,565 cases and 17,251 healthy subjects) after the elimination of heterogeneity showed an association between COMT Val108/158Met and schizophrenia [recessive model: OR 1.08 CI 95 % (1.01-1.15)]. We conducted subgroup analyses according to ethnicity. An association was observed in our Caucasian population in the additive model [OR 1.21 CI 95 % (1.06-1.37)] and in the recessive model [OR 1.21 CI 95 % (1.11-1.32)], but not in the allelic or dominant models. However, when we analysed our Asian population after the elimination of heterogeneity, no evidence of a significant association was found in any of the genetic models. Our analyses indicate that there is an association between COMT Val108/158Met and schizophrenia in the general population. Furthermore, in Caucasian populations, this risk could be increased.