The role of C957T, TaqI and Ser311Cys polymorphisms of the DRD2 gene in schizophrenia: systematic review and meta-analysis.
BACKGROUND
The association between the dopamine D2 receptor (DRD2) gene and schizophrenia has been studied though no conclusive outcomes have been attained. The aim of this study was to perform a systematic review and meta-analysis to explore the relation between three polymorphisms of the DRD2 gene (C957T, TaqI and Ser311Cys) and schizophrenia.


METHODS
The search was made in PubMed and EBSCO databases (up to February 2016). The systematic review included 34 case-control association studies (34 for C957T, 16 for TaqI and 36 for Ser311Cys). The association analysis comprised the allelic, additive, dominant, and recessive genetic models. The meta-analysis was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement.


RESULTS
The meta-analysis showed that TaqI (additive model: OR 0.57, 95% CI 0.30-1.14) and C957T (additive model: OR 0.75, 95% OR 0.58-0.97, recessive model: OR 0.79, 95% CI 0.64-0.98) exert a protective effect against developing schizophrenia. However, the sub-analysis for the C957T variant showed that this polymorphism exhibits a risk factor effect on Chinese individuals (allelic model: OR 1.33, 95% CI 1.04-1.70).


CONCLUSIONS
Our meta-analysis suggests an association of the DRD2 gene and the risk for schizophrenia, given that TaqI and C957T polymorphisms presented a protective effect against schizophrenia, and in the sub-analyses the C957T variant increased the risk for this disorder in the Chinese population.
División Académica Multidisciplinaria de Jalpa de Méndez, Universidad Juárez Autónoma de Tabasco, Jalpa de Méndez, Tabasco, Mexico.
Thelma Beatriz
TB
González-Castro
División Académica Multidisciplinaria de Jalpa de Méndez, Universidad Juárez Autónoma de Tabasco, Jalpa de Méndez, Tabasco, Mexico.
Yazmín
Y
Hernández-Díaz
División Académica de Ciencias de la Salud, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico.
Isela Esther
IE
Juárez-Rojop
Secretaría de Salud, Hospital General de Yajalón, Yajalón, Chiapas, Mexico.
María Lilia
ML
López-Narváez
División Académica Multidisciplinaria de Comalcalco, Universidad Juárez Autónoma de Tabasco, Ranchería Sur, Cuarta Sección, C.P. 86650, Comalcalco, Tabasco, Mexico. alfonso_tovillaz@yahoo.com.mx.
Carlos Alfonso
CA
Tovilla-Zárate
Secretaría de Salud, Instituto Nacional de Medicina Genómica (INMEGEN), Servicios de Atención Psiquiátrica (SAP), Ciudad de México, Mexico.
Alma
A
Genis-Mendoza
División Académica de Ciencias de la Salud, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico.
Mariela
M
Alpuin-Reyes
D000483:Alleles; D016022:Case-Control Studies; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D012307:Risk Factors; D012559:Schizophrenia / Q000235:genetics*
C581293:DRD2 protein, human; D017448:Receptors, Dopamine D2
DRD2 gene; Meta-analysis; Polymorphism; Schizophrenia; Systematic review