1Biol. Psychiatry 2004 Jan 55: 196-9
TitleA nonsense mutation in the synaptogyrin 1 gene in a family with schizophrenia.
AbstractChromosome 22q is one of the important regions repeatedly being implicated in schizophrenia. In this region, our group previously reported an association of a CAG repeat marker (22CH3) with schizophrenia in the Indian population. Because Synaptogyrin 1 (SYNGR1), associated with presynaptic vesicles in neuronal cells, lies within 1 million base pairs of this marker, it is a potential candidate gene for schizophrenia.
We sequenced all six exons and flanking splice junctions of the SYNGR1 gene. We also carried out reverse transcriptase polymerase chain reaction and Northern blot analysis for exon 2 containing transcript of the SYNGR1 gene.
We found a novel nonsense mutation (Trp27Ter) in exon 2 of the SYNGR1 gene in a family multiply affected with schizophrenia. Reverse transcriptase polymerase chain reaction and Northern blot analyses revealed that exon 2 containing transcript of this gene is expressed in the brain.
Because the SYNGR1 gene is involved in presynaptic pathways, reduced levels of this protein might play some role in the pathogenesis of schizophrenia.
SCZ Keywordsschizophrenia
2J. Hum. Genet. 2005 -1 50: 635-40
TitleSYNGR1 is associated with schizophrenia and bipolar disorder in southern India.
AbstractChromosome 22q11-13 is one of the most consistent linkage regions for schizophrenia (SCZ) and bipolar disorder (BPAD). The SYNGR1 gene, which is associated with presynaptic vesicles in neuronal cells, is located on 22q13.1. We have previously identified a novel nonsense mutation in the SYNGR1 gene in a SCZ pedigree. In the present study, a detailed analysis of this gene was performed in a case-control cohort (198 BPAD, 193 SCZ and 107 controls from southern India) to test for association with SCZ and BPAD. Sequence analysis of all exonic and flanking intronic regions of the SYNGR1 gene in 198 BPAD and 193 SCZ cases revealed a novel mutation Lsy99Glu (in one BPAD patient) and two other novel common polymorphisms [synonymous single nucleotide polymorphism (SNP--Ser97Ser) and an Asn ins/del] in the SYNGR1 gene. We also validated 9 out of 14 dbSNPs in our population. Case-control analysis revealed allelic (P = 0.028-0.00007) association of five polymorphisms with SCZ and/or BPAD cases. Further, 3-SNP (with LD block 1 SNPs) and 2-SNP (with LD block 2 SNPs) haplotype analyses did not show any association with either SCZ or BPAD. Our results support SYNGR1 as a probable susceptibility gene for SCZ and BPAD. Also, the observed association of SYNGR1 with both SCZ and BPAD suggests the likely involvement of a common pathway in the etiology of these disorders.
SCZ Keywordsschizophrenia
3Psychiatry Clin. Neurosci. 2007 Feb 61: 3-19
TitleMolecular genetics of bipolar disorder and depression.
AbstractIn this review, all papers relevant to the molecular genetics of bipolar disorder published from 2004 to the present (mid 2006) are reviewed, and major results on depression are summarized. Several candidate genes for schizophrenia may also be associated with bipolar disorder: G72, DISC1, NRG1, RGS4, NCAM1, DAO, GRM3, GRM4, GRIN2B, MLC1, SYNGR1, and SLC12A6. Of these, association with G72 may be most robust. However, G72 haplotypes and polymorphisms associated with bipolar disorder are not consistent with each other. The positional candidate approach showed an association between bipolar disorder and TRPM2 (21q22.3), GPR50 (Xq28), Citron (12q24), CHMP1.5 (18p11.2), GCHI (14q22-24), MLC1 (22q13), GABRA5 (15q11-q13), BCR (22q11), CUX2, FLJ32356 (12q23-q24), and NAPG (18p11). Studies that focused on mood disorder comorbid with somatic symptoms, suggested roles for the mitochondrial DNA (mtDNA) 3644 mutation and the POLG mutation. From gene expression analysis, PDLIM5, somatostatin, and the mtDNA 3243 mutation were found to be related to bipolar disorder. Whereas most previous positive findings were not supported by subsequent studies, DRD1 and IMPA2 have been implicated in follow-up studies. Several candidate genes in the circadian rhythm pathway, BmaL1, TIMELESS, and PERIOD3, are reported to be associated with bipolar disorder. Linkage studies show many new linkage loci. In depression, the previously reported positive finding of a gene-environmental interaction between HTTLPR (insertion/deletion polymorphism in the promoter of a serotonin transporter) and stress was not replicated. Although the role of the TPH2 mutation in depression had drawn attention previously, this has not been replicated either. Pharmacogenetic studies show a relationship between antidepressant response and HTR2A or FKBP5. New technologies for comprehensive genomic analysis have already been applied. HTTLPR and BDNF promoter polymorphisms are now found to be more complex than previously thought, and previous papers on these polymorphisms should be treated with caution. Finally, this report addresses some possible causes for the lack of replication in this field.
SCZ Keywordsschizophrenia
4J Psychiatr Res 2007 Dec 41: 1027-31
TitleIdentification of rare mutations of synaptogyrin 1 gene in patients with schizophrenia.
AbstractSynaptogyrin 1 gene (SYNGR1) is considered as a positional candidate gene for schizophrenia because of its location at chromosome 22q13, a region linked to schizophrenia, and its reduced expression in postmortem brain of patients with schizophrenia. Additionally, genetic studies also reported association of SYNGR1 is with schizophrenia and bipolar disorder in southern India. Prompted by these findings, we were interested to know if SYNGR1 is also associated with schizophrenia in our population. Therefore, we systematically searched for SYNGR1 mutations in a cohort of Han Chinese patients from Taiwan. Four single nucleotide polymorphisms (SNPs) were identified, including three at the putative core promoter region (g.-673A>C, g.-377G>A and g.-318G>T) that are in strong linkage disequilibrium and one in intron 2 (IVS2-64C>G). Computer program predicts that g.-637A>C and g.318G>T may change transcription binding sites of AP-1 and TGT3, respectively. We further carried out SNP- and haplotype-based case-control association studies of these tress SNPs with schizophrenia. However, no association was detected between these SNPs and schizophrenia in our sample. Nevertheless, we identified several rare mutations in exon 6 of SYNGR1 gene in our patient cohort (n=497), including a 3-bp (AAC) in-frame insertion between codon 202 and 203 (P202_T203insN) in two patients, an A-to-G missense mutation (c.665A>G) at codon 222 (D222G) in one patient, a synonymous mutation (c.669C>T) at codon 223 (T223T) in one patient, and a C-to-T at 3' UTR of SYNGR1 (c.772C>T) in one patient. These are mutations were not found in 507 control subjects, suggesting further functional assays are warranted to verify their relevance to the pathogenesis of schizophrenia.
SCZ Keywordsschizophrenia
5Psychiatry Res 2009 Sep 169: 167-8
TitleNo association between bipolar disorder and syngr1 or synapsin II polymorphisms in the Han Chinese population.
AbstractPolymorphisms of the SYNAPTOGYRIN1 (SYNGR1) and SYNASINII (SYNII) genes have been shown to be a risk factor for bipolar disorder or schizophrenia. A case-control study with these two genes was conducted in 506 bipolar disorder patients and 507 healthy individuals from the Han Chinese population. No association was found in this study.
SCZ Keywordsschizophrenia
6Psychiatr. Genet. 2009 Oct 19: 237-43
TitleAssociation study and mutational screening of SYNGR1 as a candidate susceptibility gene for schizophrenia.
AbstractSynaptogyrin 1 (SYNGR1) is a transmembrane protein of neurotransmitter-containing vesicle. Recently, suggestive association between SYNGR1 intragenic polymorphisms and schizophrenia has been reported in the Indian population. Furthermore, some rare nucleotide changes with a potential pathogenic effect have been found in Indian and Chinese schizophrenia patients. In this study, we have performed an association study and a resequencing analysis in an Italian sample.
Eight polymorphisms of the SYNGR1 gene were typed in a case-control sample consisting of 274 patients and 335 controls. In parallel, a mutational screening covering all SYNGR1 exons was conducted.
Evidence of association has been found for rs715505 (P = 0.028), a marker already reported to be associated with the disease. Resequencing analysis revealed two novel polymorphisms and several rare variants (13 of 16 as new variants), some of which might have relevance for gene expression and function.
The results of our association study support a contribution of SYNGR1 to schizophrenia susceptibility. In addition, the resequencing analysis evidenced mutations with a potential functional role at the mRNA and/or protein level. Of particular interest is the p.isoc:S26G missense mutation identified in six patients (0.011) and three controls (0.004) which might be involved in the elimination of a potential protein kinase C phosphorylation site.
SCZ Keywordsschizophrenia