title: Association between polymorphisms of DRD2 and DRD4 and opioid dependence: evidence from the current studies.
abstract: Several studies have assessed the association between genetic polymorphisms of DRD2 and DRD4 genes and opioid dependence risk, while the results were inconsistent. We performed a meta-analysis, including 6,846 opioid dependence cases and 4,187 controls from 22 individual studies, to evaluate the roles of four variants (DRD2 -141ins/delC, rs1799732; DRD2 311 Ser > Cys, rs1801028; DRD2-related TaqI A, rs1800497 and DRD4 exon III VNTR) in opioid dependence for the first time. We found that the -141delC polymorphism was significantly associated with increased risk of opioid dependence (homozygote comparison: odds ratios [OR], 2.71; 95% confidence interval [CI], 1.74-4.22; dominant comparison: OR, 1.27; 95% CI, 1.09-1.48). Similarly, the TaqI A1 polymorphism was also significantly increased opioid dependence risk (homozygote comparison: OR, 2.06; 95% CI, 1.25-3.42; dominant comparison: OR, 1.34; 95% CI, 1.08-1.67). Moreover, long allele (≥5-repeat) and 7-repeat allele of DRD4 exon III VNTR were found to be associated with significantly increased opioid dependence risk (OR, 1.50; 95% CI, 1.24-1.80 and OR, 1.57; 95%, 1.18-2.09, respectively). However, no association was detected between the DRD2 311 Ser > Cys polymorphism and opioid dependence. In conclusion, our results suggested that DRD2 -141ins/delC, DRD2-related TaqI A and DRD4 exon III VNTR polymorphisms might play important roles in the development of opioid dependence.
authors.affiliation: Department of Epidemiology and Health Statistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
authors.forename: Dingyan
authors.initials: D
authors.lastname: Chen
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Shang
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Song
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Miao
authors.forename: Zengzhen
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000483:Alleles; D000701:Analgesics, Opioid / Q000378:metabolism*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D009293:Opioid-Related Disorders / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4 / Q000235:genetics*
chemical_list: D000701:Analgesics, Opioid; C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4