title: The dopamine D3 receptor (DRD3) gene and risk of schizophrenia: case-control studies and an updated meta-analysis.
abstract: The dopamine D3 receptor (DRD3) has been suggested to be involved in the pathophysiology of schizophrenia. DRD3 has been tested for an association with schizophrenia, but with conflicting results. A recent meta-analysis suggested that the haplotype T-T-T-G for the SNPs rs7631540-rs1486012-rs2134655-rs963468 may confer protection against schizophrenia. However, almost all previous studies of the association between DRD3 and schizophrenia have been performed using a relatively small sample size and a limited number of markers. To assess whether DRD3 is implicated in vulnerability to schizophrenia, we conducted case-control association studies and performed an updated meta-analysis. In the first population (595 patients and 598 controls), we examined 16 genotyped single nucleotide polymorphisms (SNPs), including tagging SNPs selected from the HapMap database and SNPs detected through resequencing, as well as 58 imputed SNPs that are not directly genotyped. To confirm the results obtained, we genotyped the SNPs rs7631540-rs1486012-rs2134655-rs963468 in a second, independent population (2126 patients and 2228 controls). We also performed an updated meta-analysis of the haplotype, combining the results obtained in five populations, with a total sample size of 7551. No supportive evidence was obtained for an association between DRD3 and schizophrenia in our Japanese subjects. Our updated meta-analysis also failed to confirm the existence of a protective haplotype. To draw a definitive conclusion, further studies using larger samples and sufficient markers should be carried out in various ethnic populations.
authors.affiliation: Department of Psychiatry, Niigata University Graduate School of Medical and Dental Sciences, 757 Asahimachidori-ichibancho, Chuo-ku, Niigata 951-8510, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Nunokawa
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Naoshi
authors.initials: N
authors.lastname: Kaneko
authors.forename: Takuro
authors.initials: T
authors.lastname: Sugai
authors.forename: Saori
authors.initials: S
authors.lastname: Yazaki
authors.forename: Tadao
authors.initials: T
authors.lastname: Arinami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ujike
authors.forename: Toshiya
authors.initials: T
authors.lastname: Inada
authors.forename: Nakao
authors.initials: N
authors.lastname: Iwata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kunugi
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sasaki
authors.forename: Masanari
authors.initials: M
authors.lastname: Itokawa
authors.forename: Norio
authors.initials: N
authors.lastname: Ozaki
authors.forename: Ryota
authors.initials: R
authors.lastname: Hashimoto
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Someya
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005091:Exons / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study / Q000379:methods; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D007564:Japan; D008297:Male; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D050637:Receptors, Dopamine D3 / Q000235:genetics*; D012559:Schizophrenia / Q000235:genetics*
chemical_list: C493593:DRD3 protein, human; D050637:Receptors, Dopamine D3