| 1 | Schizophr. Res. 2008 Apr 101: 9-16 |
|---|---|
| PMID | 18329248 |
| Title | A polymorphism of the metabotropic glutamate receptor mGluR7 (GRM7) gene is associated with schizophrenia. |
| Abstract | Glutamate dysfunction has been implicated in the pathophysiology of schizophrenia. The metabotropic glutamate receptors (mGluRs) are G-protein-coupled receptors. GRM7, the gene that encodes mGluR7, is expressed in many regions of the human central nervous system. The GRM7 gene is located on human chromosome 3p26, which has been suggested by linkage analysis to contain a susceptibility locus for schizophrenia. We screened for mutations in all exons, exon/intron junctions, and promoter regions of the GRM7 gene in Japanese patients with schizophrenia and evaluated associations between the detected polymorphisms and schizophrenia. We examined the influence of one polymorphism associated with schizophrenia on the expression of GRM7 by dual-luciferase assay in transfected cells. Twenty-five polymorphisms/mutations were detected in GRM7. Case-control analysis revealed a potential association of a synonymous polymorphism (371T/C, rs3749380) in exon 1 with schizophrenia in our case-control study of 2293 Japanese patients with schizophrenia and 2382 Japanese control subjects (allelic p=0.009). Dual-luciferase assay revealed suppression of transcription activity by exon 1 containing this polymorphism and a statistically significant difference in the promoter activity between the T and C alleles. Our results support the possible association of a GRM7 gene polymorphism with genetic susceptibility to schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 2 | Psychiatry Res 2009 May 167: 88-96 |
| PMID | 19351574 |
| Title | Association study of polymorphisms in the group III metabotropic glutamate receptor genes, GRM4 and GRM7, with schizophrenia. |
| Abstract | Based on the hypothesis that a glutamatergic dysfunction is involved in the pathophysiology of schizophrenia, we have been conducting systematic studies on the association between glutamate receptor genes and schizophrenia. Here we report association studies of schizophrenia with polymorphisms in group III metabotropic glutamate receptor genes, GRM4 and GRM7. We selected 8 and 43 common SNPs distributed in the entire gene regions of GRM4 (>111 kb) and GRM7 (>900 kb), respectively. We scanned significant associations with schizophrenia using 100 case-control pairs of Japanese. We identified two neighboring SNPs (rs12491620 and rs1450099) in GRM7 showing highly significant haplotype association with schizophrenia surviving the FDR correction. We then performed additional typing of the two SNPs using the expanded sample set (404 cases and 420 controls) and confirmed the significant association with the disease. We conclude that at least one susceptibility locus for schizophrenia is located within or nearby GRM7, whereas GRM4 is unlikely to be a major susceptibility gene for schizophrenia in the Japanese population. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 3 | J Psychiatry Neurosci 2009 Nov 34: 450-8 |
| PMID | 19949721 |
| Title | Expression profiles of schizophrenia susceptibility genes during human prefrontal cortical development. |
| Abstract | Disruption in normal development of the human prefrontal cortex (PFC) may lead to cognitive dysfunction that manifests in individuals with schizophrenia. We sought to identify genes associated with age that are implicated in schizophrenia. We generated genome-wide expression profiles for the PFCs of humans ranging in age from 1 month to 49 years using the Affymetrix HG-U133 plus 2.0 microarrays (54 675 transcripts). Based on the criteria of significance (false discovery rate [FDR]-adjusted q < 0.001 and r(2) > 0.6), we identified the genes associated with age in the PFC. We then performed functional annotation analyses of age-associated genes using the Gene Ontology and the Genetic Association Database (GAD). We found robust age-dependent changes in gene expression in the PFCs of humans (2281 transcripts). The GAD analysis revealed that schizophrenia was an over-represented disease class, with 42 susceptibility genes included (p < 0.001, fold enrichment = 1.66, FDR = 1.5%). Among the 42 genes, glutamate receptor genes (GRIA1, GRIK1, GRIK2, GRIN2D, GRIP1, GRM5, GRM7 and SLC1A6) were consistently downregulated across age. We confirmed microarray gene expression changes by the quantitative polymerase chain reaction experiment. Although numerous genes undergo robust changes in expression during the PFC development, some of the changes may be confounded by known and unknown factors that are intrinsic to the postmortem brain studies. Multiple schizophrenia susceptibility genes undergo age-dependent expression changes in the human PFC, and any disruption in those genes during the critical period of development may predispose the individuals to schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 4 | Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2009 Dec 31: 664-8 |
| PMID | 20078931 |
| Title | [Association between copy number variants within metabotropic glutamate receptors 7 gene and schizophrenia]. |
| Abstract | To investigate whether genomic copy number variants (CNVs), within metabotropic glutamate receptors 7 (GRM 7) gene are associated with schizophrenia. We examined CNVs in conserved region of GRM7 using real time quantitative PCR among 180 Chinese schizophrenia cases and 33 normal controls. Products of real time quantitative PCR were sequenced bilaterally. Real time quantitative PCR found that a biallelic deletion existed at the 200 bps up-stream of exon 2 in a schizophrenia patient and a monoallelic deletion existed at this site in another 13 schizophrenia patients and a control subject. However, sequencing results showed a substitution of C to G at the 5bp up-stream of 3' end of reverse primer for real time PCR (GRM7-SV-1R). In addition, samples with this variant were exactly those having biallelic or monoallelic deletions, indicating that the results of the real time PCR were caused by the substitution variant at the 3' end of the primer rather than a bona fide genome deletion. Real-time quantitative PCR combined with sequencing can avoid false positive deletions and therefore is effective in detecting CNVs. According to our results, CNVs in GRM 7 gene is not associated with schizophrenia in the Han Chinese population. However, some potential rare CNVs may still have such relationship, and require further study. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 5 | Int. J. Neuropsychopharmacol. 2009 Oct 12: 1283-9 |
| PMID | 19638256 |
| Title | A family-based association study of DNA sequence variants in GRM7 with schizophrenia in an Indonesian population. |
| Abstract | We previously reported genome-wide significant linkage to chromosome 3p in a sib-pair family sample from Indonesia. A promising candidate gene within the linked region is the metabotropic glutamate receptor subtype 7 (GRM7), involved in glutamatergic neurotransmission. We genotyped 18 single nucleotide polymorphisms in GRM7 in the sample of 124 Indonesian sib-pair families that had provided the significant linkage finding. Transmission disequilibrium analysis revealed nominally significant transmission distortion of rs17031835 in intron 1 of GRM7 (p=0.004, before correction for multiple testing), along with haplotypes containing rs17031835. No other single marker was found to be significantly associated with schizophrenia in our sample. The results from our study provide support for the idea that glutamatergic neurotransmission and specifically the GRM7 gene might be relevant to the development of schizophrenia. Further studies supporting this finding are warranted. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 6 | J Psychiatr Res 2010 Oct 44: 971-8 |
| PMID | 20398908 |
| Title | Comprehensive copy number variant (CNV) analysis of neuronal pathways genes in psychiatric disorders identifies rare variants within patients. |
| Abstract | Copy number variations (CNV) have become an important source of human genome variability noteworthy to consider when studying genetic susceptibility to complex diseases. As recent studies have found evidences for the potential involvement of CNVs in psychiatric disorders, we have studied the dosage effect of structural genome variants as a possible susceptibility factor for different psychiatric disorders in a candidate gene approach. After selection of 68 psychiatric disorders' candidate genes overlapping with CNVs, MLPA assays were designed to determine changes in copy number of these genes. The studied sample consisted of 724 patients with psychiatric disorders (accounting for anxiety disorders, mood disorders, eating disorders and schizophrenia) and 341 control individuals. CNVs were detected in 30 out of the 68 genes screened, indicating that a considerable proportion of neuronal pathways genes contain CNVs. When testing the overall burden of rare structural genomic variants in the different psychiatric disorders compared to control individuals, there was no statistically significant difference in the total amount of gains and losses. However, 14 out of the 30 changes were only found in psychiatric disorder patients but not in control individuals. These genes include GRM7, previously associated to major depression disorder and bipolar disorder, SLC6A13, in anxiety disorders, and S100B, SSTR5 and COMT in schizophrenia. Although we have not been able to found a clear association between the studied CNVs and psychiatric disorders, the rare variants found only within the patients could account for a step further towards understanding the pathophysiology of psychiatric disorders. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 7 | ACS Chem Neurosci 2014 Dec 5: 1221-37 |
| PMID | 25225882 |
| Title | Identification of positive allosteric modulators VU0155094 (ML397) and VU0422288 (ML396) reveals new insights into the biology of metabotropic glutamate receptor 7. |
| Abstract | Metabotropic glutamate receptor 7 (mGlu7) is a member of the group III mGlu receptors (mGlus), encompassed by mGlu4, mGlu6, mGlu7, and mGlu8. mGlu7 is highly expressed in the presynaptic active zones of both excitatory and inhibitory synapses, and activation of the receptor regulates the release of both glutamate and GABA. mGlu7 is thought to be a relevant therapeutic target for a number of neurological and psychiatric disorders, and polymorphisms in the GRM7 gene have been linked to autism, depression, ADHD, and schizophrenia. Here we report two new pan-group III mGlu positive allosteric modulators, VU0155094 and VU0422288, which show differential activity at the various group III mGlus. Additionally, both compounds show probe dependence when assessed in the presence of distinct orthosteric agonists. By pairing studies of these nonselective compounds with a synapse in the hippocampus that expresses only mGlu7, we have validated activity of these compounds in a native tissue setting. These studies provide proof-of-concept evidence that mGlu7 activity can be modulated by positive allosteric modulation, paving the way for future therapeutics development. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 8 | Schizophr. Res. 2015 Mar 162: 112-7 |
| PMID | 25579050 |
| Title | Evidence for schizophrenia susceptibility alleles in the Indian population: An association of neurodevelopmental genes in case-control and familial samples. |
| Abstract | schizophrenia is a severe psychiatric disorder with lifetime prevalence of ~1% worldwide. A genotyping study was conducted using a custom panel of Illumina 1536 SNPs in 840 schizophrenia cases and 876 controls (351 patients and 385 controls from North India; and 436 patients, 401 controls and 143 familial samples with 53 probands containing 37 complete and 16 incomplete trios from South India). Meta-analysis of this population of Indo-European and Dravidian ancestry identified three strongly associated variants with schizophrenia: STT3A (rs548181, p=1.47×10(-5)), NRG1 (rs17603876, p=8.66×10(-5)) and GRM7 (rs3864075, p=4.06×10(-3)). Finally, a meta-analysis was conducted comparing our data with data from the schizophrenia Psychiatric Genome-Wide Association Study Consortium (PGC-SCZ) that supported rs548181 (p=1.39×10(-7)). In addition, combined analysis of sporadic case-control association and a transmission disequilibrium test in familial samples from South Indian population identified three associations: rs1062613 (p=3.12×10(-3)), a functional promoter variant of HTR3A; rs6710782 (p=3.50×10(-3)), an intronic variant of ERBB4; and rs891903 (p=1.05×10(-2)), an intronic variant of EBF1. The results support the risk variants observed in the earlier published work and suggest a potential role of neurodevelopmental genes in the schizophrenia pathogenesis. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 9 | Neurosci. Lett. 2015 Sep 604: 109-12 |
| PMID | 26254163 |
| Title | Association study of GRM7 polymorphisms and schizophrenia in the Chinese Han population. |
| Abstract | schizophrenia is a severe and complex mental disorder with high heritability. There is an evidence that metabotropic glutamate receptors (GRM) are associated with schizophrenia. GRM7 has been identified as a candidate gene for many psychiatric disorders especially schizophrenia. In this study, we investigated whether single nucleotide polymorphisms (SNPs) in GRM7 were associated with schizophrenia. Four SNPs (rs9814881, rs13353402, rs9870680 and rs1531939) were genotyped in 1034 schizophrenic patients and 1034 healthy controls of Chinese Han origin. The results showed that the two SNPs rs13353402 and rs1531939 demonstrated significant difference between schizophrenic patients and control subjects in allele frequencies (rs13353402: P value=0.0307, rs1531939: P value=0.0328, respectively). Nevertheless, there was no significant discrepancies in genotype distribution. In summary, our results indicate that the GRM7 SNPs rs13353402 and rs1531939 might be associated with schizophrenia in Chinese Han population. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 10 | Neurosci. Lett. 2015 Sep 604: 109-12 |
| PMID | 26254163 |
| Title | Association study of GRM7 polymorphisms and schizophrenia in the Chinese Han population. |
| Abstract | schizophrenia is a severe and complex mental disorder with high heritability. There is an evidence that metabotropic glutamate receptors (GRM) are associated with schizophrenia. GRM7 has been identified as a candidate gene for many psychiatric disorders especially schizophrenia. In this study, we investigated whether single nucleotide polymorphisms (SNPs) in GRM7 were associated with schizophrenia. Four SNPs (rs9814881, rs13353402, rs9870680 and rs1531939) were genotyped in 1034 schizophrenic patients and 1034 healthy controls of Chinese Han origin. The results showed that the two SNPs rs13353402 and rs1531939 demonstrated significant difference between schizophrenic patients and control subjects in allele frequencies (rs13353402: P value=0.0307, rs1531939: P value=0.0328, respectively). Nevertheless, there was no significant discrepancies in genotype distribution. In summary, our results indicate that the GRM7 SNPs rs13353402 and rs1531939 might be associated with schizophrenia in Chinese Han population. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 11 | Transl Psychiatry 2016 -1 6: e739 |
| PMID | 26905411 |
| Title | Antipsychotic pharmacogenomics in first episode psychosis: a role for glutamate genes. |
| Abstract | Genetic factors may underlie beneficial and adverse responses to antipsychotic treatment. These relationships may be easier to identify among patients early in the course of disease who have limited exposure to antipsychotic drugs. We examined 86 first episode patients (schizophrenia, psychotic bipolar disorder and major depressive disorder with psychotic features) who had minimal to no prior antipsychotic exposure in a 6-week pharmacogenomic study of antipsychotic treatment response. Response was measured by change in Brief Psychiatric Rating Scale total score. Risperidone monotherapy was the primary antipsychotic treatment. Pharmacogenomic association studies were completed to (1) examine candidate single-nucleotide polymorphisms (SNPs) in genes known to be involved with glutamate signaling, and (2) conduct an exploratory genome-wide association study of symptom response to identify potential novel associations for future investigation. Two SNPs in GRM7 (rs2069062 and rs2014195) were significantly associated with antipsychotic response in candidate gene analysis, as were two SNPs in the human glutamate receptor delta 2 (GRID2) gene (rs9307122 and rs1875705) in genome-wide association analysis. Further examination of these findings with those from a separate risperidone-treated study sample demonstrated that top SNPs in both studies were overrepresented in glutamate genes and that there were similarities in neurodevelopmental gene categories associated with drug response from both study samples. These associations indicate a role for gene variants related to glutamate signaling and antipsychotic response with more broad association patterns indicating the potential importance of genes involved in neuronal development. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 12 | Pharmacogenomics J. 2016 Feb -1: -1 |
| PMID | 26856250 |
| Title | The GRM7 gene, early response to risperidone, and schizophrenia: a genome-wide association study and a confirmatory pharmacogenetic analysis. |
| Abstract | The search for biomarkers of response to antipsychotic medications is hindered by difficulties inherent in the topic or related to persistent methodological difficulties, such as high rates of anticipated discontinuation and consequent distortions in the imputation of missing data. Because early response to antipsychotics represents a sufficiently reliable index of the subsequent treatment response in patients with schizophrenia, we undertook a real-world, genome-wide association study (GWAS) with the aim of identifying genetic predictors of response to risperidone after 2 weeks in 86 patients with schizophrenia. Limited to the associations reaching significance in the GWAS, confirmatory analysis relative to risperidone response over 9 months was also designed involving 97 patients (European only) enroled in the CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) genetic substudy. The GWAS revealed a significant association (false discovery rate 0.02) of the single-nucleotide polymorphism rs2133450 inside the GRM7 gene with Emsley's positive domain derived from the positive and negative syndrome scale (PANSS). Patients with the rs2133450 CC genotype presented poorer improvement in the positive domain over 2 weeks, with odds ratios of 12.68 (95% CI, 3.51-45.76) and 6.95 (95% confidence interval (CI), 2.37-20.37) compared with patients with the AA and AC genotypes, respectively. Compared with A homozygotes, rs2133450 C homozygotes enroled in the CATIE-derived confirmatory analysis showed less improvement in Emsley's positive, excited and depression domains, positive and general PANSS subtypes, and total PANSS after 9 months of treatment with risperidone. The original GWAS and the CATIE-derived confirmatory analysis support the proposal that the rs2133450 may have translational relevance as a predictor of response to risperidone.The Pharmacogenomics Journal advance online publication, 9 February 2016; doi:10.1038/tpj.2015.90. |
| SCZ Keywords | schizophrenia, schizophrenic |
| 13 | Eur Neuropsychopharmacol 2016 Jan 26: 136-46 |
| PMID | 26655190 |
| Title | Significant association of GRM7 and GRM8 genes with schizophrenia and major depressive disorder in the Han Chinese population. |
| Abstract | Metabotropic glutamate receptor type 7 (GRM7) and type 8 (GRM8) are involved in the neurotransmission of glutamate which is supposed to play an important role in the development of schizophrenia (SCZ) and major depressive disorders (MDD). We designed this study to investigate whether common DNA variants or their genetic interactions within GRM7 and GMR8 genes were associated with these disorders in the Han Chinese population. Fourteen SNPs in GRM7 and GRM8 were selected within a sample set comprising 1235 SCZ patients, 1045 MDD patients and 1235 normal controls. Significant association in SCZ case-control subjects was observed for rs2229902 (permutated Pallele=0.0005, OR=1.492 [95% CI=1.231-1.807]) and rs9870680 (permutated Pallele=0.0023, OR=1.262 [95% CI=1.116-1.426]) in GRM7 and rs2237781 (permutated Pallele=0.0027, OR=1.346 [95% CI=1.149-1.575]) in GRM8. Association analysis for MDD case-control subjects revealed positive results in rs779706 (permutated Pallele=0.0099, OR=1.237 [95% CI=1.093-1.399]) of GRM7 and in rs1361995 (permutated Pallele=0.0017, OR=1.488 [95% CI=1.215-1.823]) of GRM8. Moreover, a three-locus model, constituted by polymorphisms in GRM7 and GRM8 significantly correlated with MDD in the gene-gene interaction analysis. Meta-analysis and haplotype analysis further confirmed our significant results. We demonstrated the genetic association of GRM7 and GRM8 with SCZ and MDD in the Han Chinese population. We also found susceptibility interactive effects of these two genes with both psychiatric disorders, which might provide new insights into the etiology of them. |
| SCZ Keywords | schizophrenia, schizophrenic |