title: Associations between dopamine D2 receptor gene polymorphisms and schizophrenia risk: a PRISMA compliant meta-analysis.
abstract: OBJECTIVE
  To determine the relationships between dopamine D2 receptor gene polymorphisms and the risk of schizophrenia using meta-analysis.
  
  
  METHODS
  The PubMed, Embase, and China National Knowledge Infrastructure databases were searched to identify relevant literature published up to February 2016. The allele contrast model was used. Stata software was used for statistical analysis, with odds ratios (ORs) and 95% confidence intervals (CIs) calculated to evaluate the associations between dopamine D2 receptor gene polymorphisms and the risk of schizophrenia. Meta-regression and publication bias, trim-and-fill, subgroup, sensitivity, cumulative, and fail-safe number analyses were also performed.
  
  
  RESULTS
  This meta-analysis included 81 studies. The rs1801028 and rs1799732 were associated with schizophrenia risk among Asians (P=0.04, OR =1.25, 95% CI =1.01-1.55;P<0.01, OR =0.76, 95% CI =0.63-0.92, respectively), while the rs6277 was associated with schizophrenia risk in Caucasians (P<0.01, OR=0.72, 95% CI =0.66-0.79). The rs1800497 was also associated with schizophrenia risk in population-based controls (P<0.01, OR =0.84, 95% CI =0.72-0.97). The rs6275, rs1079597, and rs1800498 were not associated with schizophrenia risk. In addition, meta-regression indicated that the controls may be sources of heterogeneity for the rs1801028 single-nucleotide polymorphism (SNP), while ethnicity may be sources of heterogeneity for the rs6277 SNP. Publication bias was significant for the rs1801028 SNP, and this result changed after the publication bias was adjusted using the trim-and-fill method.
  
  
  CONCLUSIONS
  This meta-analysis demonstrated that the rs1801028 may be a risk factor for susceptibility to schizophrenia among Asians, while the rs1799732 may be a protective factor for that population. Large-sample studies are necessary to verify the results of this meta-analysis.
authors.affiliation: Clinical Research Center, The First Affiliated Hospital of Xi'an Jiaotong University.
authors.forename: Hairong
authors.initials: H
authors.lastname: He
authors.affiliation: Clinical Research Center, The First Affiliated Hospital of Xi'an Jiaotong University; College of Pharmacy, Xi'an Medical University.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Wu
authors.affiliation: Clinical Research Center, The First Affiliated Hospital of Xi'an Jiaotong University.
authors.forename: Lihong
authors.initials: L
authors.lastname: Yang
authors.affiliation: Clinical Research Center, The First Affiliated Hospital of Xi'an Jiaotong University.
authors.forename: Fan
authors.initials: F
authors.lastname: Gao
authors.affiliation: Department of Psychiatry, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Department of Psychiatry, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Junqin
authors.initials: J
authors.lastname: Feng
authors.affiliation: Clinical Research Center, The First Affiliated Hospital of Xi'an Jiaotong University; Department of Psychiatry, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Xiancang
authors.initials: X
authors.lastname: Ma
keywords: dopamine D2 receptor; polymorphisms; schizophrenia