title: CYP2D6*4 allele polymorphism increases the risk of Parkinson's disease: evidence from meta-analysis.
abstract: BACKGROUND
  Many epidemiological studies have been conducted to explore the association between a single CYP2D6 gene polymorphism and Parkinson's disease (PD) susceptibility. However, the results remain controversial.
  
  
  OBJECTIVE
  To clarify the effects of a single CYP2D6 gene polymorphism on the risk of PD, a meta-analysis of all available studies relating to CYP2D6*4 polymorphism and the risk of PD was conducted.
  
  
  METHODS
  A comprehensive literature search of PubMed, EMBASE, and the China National Knowledge Infrastructure (CNKI) up to September 1, 2013 was conducted. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) were calculated. Meta-regression, Galbraith plots, subgroup analysis, sensitivity analysis, and publication bias analysis were also performed.
  
  
  RESULTS
  Twenty-two separate comparisons consisting of 2,629 patients and 3,601 controls were included in our meta-analysis. The pooled analyses showed a significant association between CYP2D6*4G/A polymorphism and PD risk in all of the comparisons (A vs. G allele: OR = 1.28, 95% CI = 1.14-1.43, P = 0.001; AA vs. GG: OR = 1.43, 95% CI = 1.06-1.93, P = 0.018; AG vs. GG: OR = 1.22, 95% CI = 1.06-1.40, P = 0.006; AG+AA vs. GG: OR = 1.26, 95% CI = 1.10-1.44, P = 0.001; AA vs. AG+GG: OR = 1.37, 95% CI = 1.02-1.83, P = 0.036). In subgroup analysis stratified by ethnicity, significant associations were also demonstrated in Caucasians but not in Asians. No significant association was found in subgroup analysis stratified by age of onset or disease form.
  
  
  CONCLUSIONS
  We concluded that the CYP2D6*4G/A polymorphism denotes an increased genetic susceptibility to PD in the overall population, especially in Caucasians. Further large and well-designed studies are needed to confirm this association.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Cuiju
authors.initials: C
authors.lastname: Mo
authors.affiliation: Department of Geriatrics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Chen
authors.affiliation: Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Yantong
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Qiliu
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.affiliation: Department of Clinical Laboratory, Liuzhou City People's Hospital, Liuzhou, Guangxi, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
mesh_terms: D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics*; D018740:Genetic Heterogeneity; D006801:Humans; D016017:Odds Ratio; D010300:Parkinson Disease / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D044465:White People / Q000235:genetics
chemical_list: D019389:Cytochrome P-450 CYP2D6