title: Brain-Derived Neurotrophic Factor Gene Val66Met Polymorphism and Risk of Schizophrenia: A Meta-analysis of Case-Control Studies.
abstract: According to evidences from previous family and association studies, it has been claimed that genetic factors are involved in the neuropathogenesis of Schizophrenia disorder. Whether the Val66Met variant of brain-derived neurotrophic factor (BDNF) gene plays any roles in the pathogenesis of this syndrome or could be a potential biomarker for prognosis of this disorder has been a long-standing controversial issue. We performed a meta-analysis restricted to case-control studies and searched Pubmed, PsychInfo, and Google scholar using keywords including 'association,' 'Val66Met,' 'BDNF,' and 'schizophrenia' published up to May 1, 2015. A total of 39 studies for schizophrenia were combined by fixed- and random-effects models. The pooled results from the schizophrenia sample indicated no significant evidence for the association of Val/Val and Val/Met genotypes of BDNF gene with schizophrenia, but it was observed that there is an association between Met/Met polymorphism and schizophrenia in Asian, European, and Chinese populations, this means that the risk of schizophrenia in Asian, European, and Chinese populations with Met/Met genotype is, respectively, 9, 26, and 9%. There was a significant association between BDNF Val66Met polymorphism and schizophrenia in our meta-analysis study. We cannot rule out the possibility that other polymorphisms in the BDNF gene are involved in the pathophysiology of schizophrenia. In addition, more studies should be conducted on the polymorphisms in other genes to elucidate their possible roles in schizophrenia.
authors.affiliation: Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-communicable Disease and Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, P.O. Box: 81746-73461, Isfahan, Iran. mkheirollahi@med.mui.ac.ir.
authors.forename: Majid
authors.initials: M
authors.lastname: Kheirollahi
authors.affiliation: Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-communicable Disease and Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, P.O. Box: 81746-73461, Isfahan, Iran. kazemielahe89@yahoo.com.
authors.forename: Elahe
authors.initials: E
authors.lastname: Kazemi
authors.affiliation: Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Non-communicable Disease and Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, P.O. Box: 81746-73461, Isfahan, Iran. saeede_ashoori@yahoo.com.
authors.forename: Saeideh
authors.initials: S
authors.lastname: Ashouri
mesh_terms: D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D016022:Case-Control Studies; D005006:Ethnicity / Q000235:genetics; D005787:Gene Frequency / Q000235:genetics; D020022:Genetic Predisposition to Disease; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017594:Publication Bias; D012559:Schizophrenia / Q000235:genetics*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human
keywords: BDNF; Meta-analysis; Schizophrenia; Val66Met polymorphism