title: Association analysis of group II metabotropic glutamate receptor genes (GRM2 and GRM3) with mood disorders and fluvoxamine response in a Japanese population.
abstract: BACKGROUND
  Several lines of evidence implicate abnormalities in glutamate neural transmission in the pathophysiology of mood disorders, including major depressive disorder (MDD) and bipolar disorder (BP). Preclinical antidepressant effects were also reported for group II metabotropic glutamate receptor (Group II mGluRs) antagonists show dose-dependent antidepressant-like effects in murine models of depression. Also, it has been suggested that abnormalities in the hypothalamic-pituitary-adrenal axis and serotonergic neural transmission are important mechanisms in the pathophysiology of mood disorders. Group II mGluRs play an important role in regulating the function of these mechanisms. From these results, it has been suggested that abnormalities in Group II mGluRs might be involved in the pathophysiology of mood disorders, including MDD) and BP, and may influence the clinical response to treatment with SSRIs in MDD. Therefore, we studied the association between Group II mGluR genes (GRM2 and GRM3) and mood disorders and the efficacy of fluvoxamine treatment in Japanese MDD patients.
  
  
  METHODS
  Using three tagging SNPs in GRM2 and an SNP (rs6465084) reported functional variant in GRM3, we conducted a genetic association analysis of case-control samples (325 MDD patients, 155 BP patients and 802 controls) in the Japanese population. In addition, we performed an association analysis of GRM2 and GRM3 and the efficacy of fluvoxamine treatment in 117 Japanese patients with MDD. The MDD patients in this study had scores of 12 or higher on the 17 items of the Structured Interview Guide for Hamilton Rating Scale for Depression (SIGH-D). We defined a clinical response as a decrease of more than 50% in baseline SIGH-D within 8 weeks, and clinical remission as an SIGH-D score of less than 7 at 8 weeks.
  
  
  RESULTS
  We found an association between rs6465084 in GRM3 and MDD in the allele-wise analysis after Bonferroni's correction (P-value=0.0371). However, we did not find any association between GRM3 and BP or the fluvoxamine therapeutic response in MDD in the allele/genotype-wise analysis. We also did not detect any association between GRM2 and MDD, BP or the fluvoxamine therapeutic response in MDD in the allele/genotype-wise or haplotype-wise analysis.
  
  
  CONCLUSIONS
  We detected an association between only one marker (rs6465084) in GRM3 and Japanese MDD patients. However, because we did not perform an association analysis based on LD and a mutation scan of GRM3, a replication study using a larger sample and based on LD may be required for conclusive results.
authors.affiliation: Department of Psychiatry, Fujita Health University School of Medicine, Toyoake, Aichi, 470-1192, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tsunoka
authors.forename: Taro
authors.initials: T
authors.lastname: Kishi
authors.forename: Masashi
authors.initials: M
authors.lastname: Ikeda
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kitajima
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamanouchi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kinoshita
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Kawashima
authors.forename: Tomo
authors.initials: T
authors.lastname: Okochi
authors.forename: Takenori
authors.initials: T
authors.lastname: Okumura
authors.forename: Toshiya
authors.initials: T
authors.lastname: Inada
authors.forename: Norio
authors.initials: N
authors.lastname: Ozaki
authors.forename: Nakao
authors.initials: N
authors.lastname: Iwata
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D016666:Fluvoxamine / Q000627:therapeutic use*; D005787:Gene Frequency / Q000235:genetics; D055106:Genome-Wide Association Study / Q000379:methods; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000188:drug therapy* / Q000235:genetics*; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics*; D055815:Young Adult
chemical_list: D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; D016666:Fluvoxamine