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Schwarz E. A gene-based review of RGS4 as a putative risk gene for psychiatric illness. Am J Med Genet B Neuropsychiatr Genet 2018; 177:267-273. [PMID: 28544755 DOI: 10.1002/ajmg.b.32547] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
Considerable efforts have been made to characterize RGS4 as a potential candidate gene for schizophrenia. Investigations span across numerous modalities and include explorations of genetic risk associations, mRNA and protein levels in the brain, and functionally relevant interactions with other candidate genes as well as links to schizophrenia relevant neural phenotypes. While these lines of investigations have yielded partially inconsistent findings, they provide a perspective on RGS4 as an important part of a larger biological system contributing to schizophrenia risk. This gene-based review aims to provide a comprehensive overview of published data from different experimental modalities and discusses the current knowledge of RGS4's systems-biological impact on the schizophrenia pathology.
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Affiliation(s)
- Emanuel Schwarz
- Medical Faculty Mannheim, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Heidelberg University, Mannheim, Germany
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Abstract
Large-scale genomic investigations have just begun to illuminate the molecular genetic contributions to major psychiatric illnesses, ranging from small-effect-size common variants to larger-effect-size rare mutations. The findings provide causal anchors from which to understand their neurobiological basis. Although these studies represent enormous success, they highlight major challenges reflected in the heterogeneity and polygenicity of all of these conditions and the difficulty of connecting multiple levels of molecular, cellular, and circuit functions to complex human behavior. Nevertheless, these advances place us on the threshold of a new frontier in the pathophysiological understanding, diagnosis, and treatment of psychiatric disease.
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Affiliation(s)
- Daniel H Geschwind
- Departments of Neurology, Psychiatry, and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Jonathan Flint
- Wellcome Trust Center for Human Genetics, University of Oxford, Oxford, UK.
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Singh S, Kumar A, Agarwal S, Phadke SR, Jaiswal Y. Genetic insight of schizophrenia: past and future perspectives. Gene 2013; 535:97-100. [PMID: 24140491 DOI: 10.1016/j.gene.2013.09.110] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 09/26/2013] [Indexed: 11/28/2022]
Abstract
Schizophrenia (SCZ) has a heritability of about 80%, and the search for the genetic basis of this disease has been frustrating. Because schizophrenia has no distinguishing pathology or diagnostic criteria, it is difficult to relate gene changes to discrete physiological or biochemical changes associated with the disease. Schizophrenia fits the profile of a complex disorder in which multiple genes interact along with environmental influences to produce a range of phenotypes. There is accumulating evidence that both common genetic variants with small effects and rare genetic lesions with large effects determine risk of SCZ. As recently shown, thousands of common single nucleotide polymorphisms (SNPs), each with small effect, cumulatively could explain about 30% of the underlying genetic risk of SCZ. The ability of positional genetics to implicate novel genes and pathways will open up new vistas for neurobiological research, and all the signs are that genetic research is poised to deliver crucial insights into the nature of schizophrenia. In this review, we outline a general theoretical background of genetic mechanisms involved in SCZ.
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Affiliation(s)
- Shweta Singh
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS), Lucknow 226014, India.
| | - Ashok Kumar
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS), Lucknow 226014, India.
| | - Sarita Agarwal
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS), Lucknow 226014, India.
| | - Shubha R Phadke
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS), Lucknow 226014, India.
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Levinson DF, Shi J, Wang K, Oh S, Riley B, Pulver AE, Wildenauer DB, Laurent C, Mowry BJ, Gejman PV, Owen MJ, Kendler KS, Nestadt G, Schwab SG, Mallet J, Nertney D, Sanders AR, Williams NM, Wormley B, Lasseter VK, Albus M, Godard-Bauché S, Alexander M, Duan J, O'Donovan MC, Walsh D, O'Neill A, Papadimitriou GN, Dikeos D, Maier W, Lerer B, Campion D, Cohen D, Jay M, Fanous A, Eichhammer P, Silverman JM, Norton N, Zhang N, Hakonarson H, Gao C, Citri A, Hansen M, Ripke S, Dudbridge F, Holmans PA. Genome-wide association study of multiplex schizophrenia pedigrees. Am J Psychiatry 2012; 169:963-73. [PMID: 22885689 PMCID: PMC6927206 DOI: 10.1176/appi.ajp.2012.11091423] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The authors used a genome-wide association study (GWAS) of multiply affected families to investigate the association of schizophrenia to common single-nucleotide polymorphisms (SNPs) and rare copy number variants (CNVs). METHOD The family sample included 2,461 individuals from 631 pedigrees (581 in the primary European-ancestry analyses). Association was tested for single SNPs and genetic pathways. Polygenic scores based on family study results were used to predict case-control status in the Schizophrenia Psychiatric GWAS Consortium (PGC) data set, and consistency of direction of effect with the family study was determined for top SNPs in the PGC GWAS analysis. Within-family segregation was examined for schizophrenia-associated rare CNVs. RESULTS No genome-wide significant associations were observed for single SNPs or for pathways. PGC case and control subjects had significantly different genome-wide polygenic scores (computed by weighting their genotypes by log-odds ratios from the family study) (best p=10(-17), explaining 0.4% of the variance). Family study and PGC analyses had consistent directions for 37 of the 58 independent best PGC SNPs (p=0.024). The overall frequency of CNVs in regions with reported associations with schizophrenia (chromosomes 1q21.1, 15q13.3, 16p11.2, and 22q11.2 and the neurexin-1 gene [NRXN1]) was similar to previous case-control studies. NRXN1 deletions and 16p11.2 duplications (both of which were transmitted from parents) and 22q11.2 deletions (de novo in four cases) did not segregate with schizophrenia in families. CONCLUSIONS Many common SNPs are likely to contribute to schizophrenia risk, with substantial overlap in genetic risk factors between multiply affected families and cases in large case-control studies. Our findings are consistent with a role for specific CNVs in disease pathogenesis, but the partial segregation of some CNVs with schizophrenia suggests that researchers should exercise caution in using them for predictive genetic testing until their effects in diverse populations have been fully studied.
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Affiliation(s)
- Douglas F Levinson
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, Calif., USA.
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Holmans PA, Riley B, Pulver AE, Owen MJ, Wildenauer DB, Gejman PV, Mowry BJ, Laurent C, Kendler KS, Nestadt G, Williams NM, Schwab SG, Sanders AR, Nertney D, Mallet J, Wormley B, Lasseter VK, O'Donovan MC, Duan J, Albus M, Alexander M, Godard S, Ribble R, Liang KY, Norton N, Maier W, Papadimitriou G, Walsh D, Jay M, O'Neill A, Lerer FB, Dikeos D, Crowe RR, Silverman JM, Levinson DF. Genomewide linkage scan of schizophrenia in a large multicenter pedigree sample using single nucleotide polymorphisms. Mol Psychiatry 2009; 14:786-95. [PMID: 19223858 PMCID: PMC2714870 DOI: 10.1038/mp.2009.11] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 11/20/2008] [Accepted: 11/25/2008] [Indexed: 12/15/2022]
Abstract
A genomewide linkage scan was carried out in eight clinical samples of informative schizophrenia families. After all quality control checks, the analysis of 707 European-ancestry families included 1615 affected and 1602 unaffected genotyped individuals, and the analysis of all 807 families included 1900 affected and 1839 unaffected individuals. Multipoint linkage analysis with correction for marker-marker linkage disequilibrium was carried out with 5861 single nucleotide polymorphisms (SNPs; Illumina version 4.0 linkage map). Suggestive evidence for linkage (European families) was observed on chromosomes 8p21, 8q24.1, 9q34 and 12q24.1 in nonparametric and/or parametric analyses. In a logistic regression allele-sharing analysis of linkage allowing for intersite heterogeneity, genomewide significant evidence for linkage was observed on chromosome 10p12. Significant heterogeneity was also observed on chromosome 22q11.1. Evidence for linkage across family sets and analyses was most consistent on chromosome 8p21, with a one-LOD support interval that does not include the candidate gene NRG1, suggesting that one or more other susceptibility loci might exist in the region. In this era of genomewide association and deep resequencing studies, consensus linkage regions deserve continued attention, given that linkage signals can be produced by many types of genomic variation, including any combination of multiple common or rare SNPs or copy number variants in a region.
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Affiliation(s)
- P A Holmans
- Department of Psychological Medicine, School of Medicine, Cardiff University, Cardiff, UK
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Porteous D. Genetic causality in schizophrenia and bipolar disorder: out with the old and in with the new. Curr Opin Genet Dev 2008; 18:229-34. [DOI: 10.1016/j.gde.2008.07.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Accepted: 07/04/2008] [Indexed: 01/15/2023]
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Chen QY, Chen Q, Feng GY, Lindpaintner K, Wang LJ, Chen ZX, Gao ZS, Tang JS, Huang G, He L. Case-control association study of Disrupted-in-Schizophrenia-1 (DISC1) gene and schizophrenia in the Chinese population. J Psychiatr Res 2007; 41:428-34. [PMID: 16524593 DOI: 10.1016/j.jpsychires.2006.01.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 01/04/2006] [Accepted: 01/10/2006] [Indexed: 11/16/2022]
Abstract
Disrupted-in-Schizophrenia-1 (DISC1) has first been identified as a candidate gene for schizophrenia through study of a Scottish family with a balanced (1; 11) (q42.1; q14.3) translocation. Lots of linkage and association studies supported DISC1 as a risk factor for schizophrenia. In this study, we genotyped three SNPs in DISC1 using a set of Han Chinese samples of 560 schizophrenics and 576 controls. No positive association was detected in the whole samples but analysis of allele frequencies in female samples showed weak association between SNP rs2295959 and the disease (chi(2)=6.188, P=0.0135, OR=0.728, 95% CI=0.567-0.935). Our results provide further evidence for sex difference for the effect of the gene on the aetiology of schizophrenia. Our findings also would encourage further studies, particularly family-based association studies with larger samples, to analyze the association between DISC1 and schizophrenia.
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Affiliation(s)
- Qing-Ying Chen
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 319 Yue Yang Road, Shanghai 200031, PR China
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Jang YL, Kim JW, Lee YS, Park DY, Cho EY, Jeun HO, Lee D, Hong KS. Linkage of schizophrenia with chromosome 1q32 in Korean multiplex families. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:279-84. [PMID: 17171664 DOI: 10.1002/ajmg.b.30389] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromosome 1q contains a few loci for which modest evidence of linkage with schizophrenia has been reported in several independent studies. However, markers showing the peak linkage signal are dispersed over a large chromosomal region. In addition, inconsistent findings have been generated from different populations or different subgroups of the same populations. The purpose of the current study is to determine whether those loci are linked to schizophrenia in the Korean population. We investigated 46 Korean multiplex schizophrenia families, initially using 11 microsatellite markers spanning around 91 cM region of 1p22 approximately 42. In a non-parametric linkage analysis, D1S249 located on 1q32.1 showed statistical evidence suggestive of linkage. At the second stage analysis for narrowing down the region, four additional nearby markers were genotyped. In the single point analysis, we found another suggestive linkage signal at D1S2891. The highest NPL score of 2.67 (P = 0.0039) was obtained in the multi-point analysis. This study provides supportive evidence for linkage of chromosome 1q32 with schizophrenia.
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Affiliation(s)
- Yong Lee Jang
- Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kagnam-Gu, Seoul, Korea
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Transcriptome alterations in schizophrenia: disturbing the functional architecture of the dorsolateral prefrontal cortex. PROGRESS IN BRAIN RESEARCH 2007; 158:141-52. [PMID: 17027695 DOI: 10.1016/s0079-6123(06)58007-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
The availability of methods for quantifying tissue concentrations of messenger RNAs in the postmortem of the human brain has provided a number of new findings in schizophrenia. However, understanding how these findings actually relate to the disease process of schizophrenia requires knowledge both of the factors that might give rise to such changes in gene expression and of the impact of these changes on the function of the affected neural circuits. Consequently, this chapter provides a review of the potential causes and consequences of some of the schizophrenia-related transcriptome changes in the dorsolateral prefrontal cortex, a brain region implicated in the pathophysiology of certain core cognitive deficits in this illness.
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Venken T, Del-Favero J. Chasing genes for mood disorders and schizophrenia in genetically isolated populations. Hum Mutat 2007; 28:1156-70. [PMID: 17659644 DOI: 10.1002/humu.20582] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Major affective disorders and schizophrenia are among the most common brain diseases worldwide and their predisposition is influenced by a complex interaction of genetic and environmental factors. So far, traditional linkage mapping studies for these complex disorders have not achieved the same success as the positional cloning of genes for Mendelian diseases. The struggle to identify susceptibility genes for complex disorders has stimulated the development of alternative approaches, including studies in genetically isolated populations. Since isolated populations are likely to have both a reduced number of genetic vulnerability factors and environmental background and are therefore considered to be more homogeneous compared to outbred populations, the use of isolated populations in genetic studies is expected to improve the chance of finding susceptibility loci and genes. Here we review the role of isolated populations, based on linkage and association studies, in the identification of susceptibility genes for bipolar disorder and schizophrenia.
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Affiliation(s)
- Tine Venken
- Applied Molecular Genomics Group, Department of Molecular Genetics, VIB, Antwerpen, Belgium
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Seeman P, Schwarz J, Chen JF, Szechtman H, Perreault M, McKnight GS, Roder JC, Quirion R, Boksa P, Srivastava LK, Yanai K, Weinshenker D, Sumiyoshi T. Psychosis pathways converge via D2high dopamine receptors. Synapse 2006; 60:319-46. [PMID: 16786561 DOI: 10.1002/syn.20303] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The objective of this review is to identify a target or biomarker of altered neurochemical sensitivity that is common to the many animal models of human psychoses associated with street drugs, brain injury, steroid use, birth injury, and gene alterations. Psychosis in humans can be caused by amphetamine, phencyclidine, steroids, ethanol, and brain lesions such as hippocampal, cortical, and entorhinal lesions. Strikingly, all of these drugs and lesions in rats lead to dopamine supersensitivity and increase the high-affinity states of dopamine D2 receptors, or D2High, by 200-400% in striata. Similar supersensitivity and D2High elevations occur in rats born by Caesarian section and in rats treated with corticosterone or antipsychotics such as reserpine, risperidone, haloperidol, olanzapine, quetiapine, and clozapine, with the latter two inducing elevated D2High states less than that caused by haloperidol or olanzapine. Mice born with gene knockouts of some possible schizophrenia susceptibility genes are dopamine supersensitive, and their striata reveal markedly elevated D2High states; suchgenes include dopamine-beta-hydroxylase, dopamine D4 receptors, G protein receptor kinase 6, tyrosine hydroxylase, catechol-O-methyltransferase, the trace amine-1 receptor, regulator of G protein signaling RGS9, and the RIIbeta form of cAMP-dependent protein kinase (PKA). Striata from mice that are not dopamine supersensitive did not reveal elevated D2High states; these include mice with knockouts of adenosine A2A receptors, glycogen synthase kinase GSK3beta, metabotropic glutamate receptor 5, dopamine D1 or D3 receptors, histamine H1, H2, or H3 receptors, and rats treated with ketanserin or aD1 antagonist. The evidence suggests that there are multiple pathways that convergetoelevate the D2High state in brain regions and that this elevation may elicit psychosis. This proposition is supported by the dopamine supersensitivity that is a common feature of schizophrenia and that also occurs in many types of genetically altered, drug-altered, and lesion-altered animals. Dopamine supersensitivity, in turn, correlates with D2High states. The finding that all antipsychotics, traditional and recent ones, act on D2High dopamine receptors further supports the proposition.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, University of Toronto, and Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5S 1A8.
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Liu YL, Fann CSJ, Liu CM, Chen WJ, Wu JY, Hung SI, Chen CH, Jou YS, Liu SK, Hwang TJ, Hsieh MH, Ouyang WC, Chan HY, Chen JJ, Yang WC, Lin CY, Lee SFC, Hwu HG. A single nucleotide polymorphism fine mapping study of chromosome 1q42.1 reveals the vulnerability genes for schizophrenia, GNPAT and DISC1: Association with impairment of sustained attention. Biol Psychiatry 2006; 60:554-62. [PMID: 16997000 DOI: 10.1016/j.biopsych.2006.04.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 04/21/2006] [Accepted: 04/25/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND The marker D1S251 of chromosome 1q42.1 showed significant association with schizophrenia in a Taiwanese sample. We used single nucleotide polymorphism (SNP) fine mapping to search for the vulnerability genes of schizophrenia. METHODS We selected 120 SNPs covering 1 Mb around D1S251 from the public database. These selected SNPs were initially validated if allele frequency was >10%. Forty-seven validated SNPs were genotyped in 102 families with at least 2 siblings affected with schizophrenia. RESULTS Two SNP blocks showed significant association with schizophrenia. Block 1 (five-SNP), located between intron 2 and intron 13 of the glyceronephosphate O-acyltransferase (GNPAT) gene, showed the most significant associations using single-locus TDT (z = -2.07, p = .038, df = 1) and haplotype association analyses (z = -1.99, p = .046, df = 1). Block 2 (two-SNP), located between intron 4 and intron 5 of the disrupted-in-schizophrenia 1 (DISC1) gene, also showed the most significant results in both the single-locus (z = -3.22, p = .0013, df = 1) and haplotype association analyses (z = 3.35, p = .0008, df = 1). The association of the DISC1 gene with schizophrenia was mainly in the patient group with sustained attention deficits as assessed by the Continuous Performance Test. CONCLUSIONS Chromosome 1q42.1 harbors GNPAT and DISC1 as candidate genes for schizophrenia, and DISC1 is associated with sustained attention deficits.
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Affiliation(s)
- Yu-Li Liu
- Division of Mental Health and Substance Abuse Research, National Health Research Institutes, Taipei, Taiwan
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Abstract
The study of schizophrenia genetics has confirmed the importance of genes in etiology, but has not so far identified the relationship between observed genetic risks and specific DNA variants, protein alterations or biological processes. In spite of many limitations, numerous regions of the human genome give consistent, although by no means unanimous, support for linkage, which is unlikely to occur by chance. Two recent shifts have been evident in the field. First, a series of studies combining linkage and association analyses in the same family sets have identified promising candidate genes (DTNBP1, NRG1, G72/G30, TRAR4). Although a consensus definition of replication for genetic association in a complex trait remains difficult to achieve, the evidence for two of these (dystrobrevin binding protein 1 (DTNBP1), NRG1) is strong. Second, a series of studies combining association with functional investigation of changes in the associated gene in schizophrenia have also identified several candidate genes (COMT, RGS4, PPP3CC, ZDHHC8, AKT1). Somewhat surprisingly, the loci implicated by these studies have proven less robust in replication, although the number of replication studies remains small in several cases. Assessment of the combined evidence for the DTNBP1 gene gives some insight into the nature of the problems remaining to be solved.
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Affiliation(s)
- Brien Riley
- Department of Psychiatry, Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA.
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Mah S, Nelson MR, Delisi LE, Reneland RH, Markward N, James MR, Nyholt DR, Hayward N, Handoko H, Mowry B, Kammerer S, Braun A. Identification of the semaphorin receptor PLXNA2 as a candidate for susceptibility to schizophrenia. Mol Psychiatry 2006; 11:471-8. [PMID: 16402134 DOI: 10.1038/sj.mp.4001785] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The discovery of genetic factors that contribute to schizophrenia susceptibility is a key challenge in understanding the etiology of this disease. Here, we report the identification of a novel schizophrenia candidate gene on chromosome 1q32, plexin A2 (PLXNA2), in a genome-wide association study using 320 patients with schizophrenia of European descent and 325 matched controls. Over 25,000 single-nucleotide polymorphisms (SNPs) located within approximately 14,000 genes were tested. Out of 62 markers found to be associated with disease status, the most consistent finding was observed for a candidate locus on chromosome 1q32. The marker SNP rs752016 showed suggestive association with schizophrenia (odds ratio (OR) = 1.49, P = 0.006). This result was confirmed in an independent case-control sample of European Americans (combined OR = 1.38, P = 0.035) and similar genetic effects were observed in smaller subsets of Latin Americans (OR = 1.26) and Asian Americans (OR = 1.37). Supporting evidence was also obtained from two family-based collections, one of which reached statistical significance (OR = 2.2, P = 0.02). High-density SNP mapping showed that the region of association spans approximately 60 kb of the PLXNA2 gene. Eight out of 14 SNPs genotyped showed statistically significant differences between cases and controls. These results are in accordance with previous genetic findings that identified chromosome 1q32 as a candidate region for schizophrenia. PLXNA2 is a member of the transmembrane semaphorin receptor family that is involved in axonal guidance during development and may modulate neuronal plasticity and regeneration. The PLXNA2 ligand semaphorin 3A has been shown to be upregulated in the cerebellum of individuals with schizophrenia. These observations, together with the genetic results, make PLXNA2 a likely candidate for the 1q32 schizophrenia susceptibility locus.
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Affiliation(s)
- S Mah
- Sequenom Inc., San Diego, CA 92121, USA
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Talkowski ME, Chowdari KV, Lewis DA, Nimgaonkar VL. Can RGS4 polymorphisms be viewed as credible risk factors for schizophrenia? A critical review of the evidence. Schizophr Bull 2006; 32:203-8. [PMID: 16469939 PMCID: PMC2632201 DOI: 10.1093/schbul/sbj058] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There has been a recent explosion in the list of putative susceptibility genes for schizophrenia (SZ). These genes have been identified on the basis of presumed pathogenesis, linkage, and genetic association studies. While several promising candidates have arisen, identification of a conclusive genetic risk factor has remained elusive. The proof would be most compelling if it stemmed from all three of these domains. In this review, we consider such evidence in relation to the regulator of G-protein signaling 4 (RGS4), a gene localized to chromosome 1q23. Disorder-specific changes in RGS4 mRNA levels have been observed in post-mortem brain samples; linkage has been reported at chromosome 1q23; and several association studies have concluded that significant associations exist. The latter are supported by a recently conducted meta-analysis. Thus, there is suggestive evidence in each of these domains implicating a role for RGS4 in SZ susceptibility. However, analogous to other promising susceptibility candidates, the nature of the genetic association, the precise polymorphism(s) conferring risk, and the functional implications of sequence variation at this gene are unclear. We review the published data and place them in the context of suggested criteria for establishing a candidate gene as a credible susceptibility factor for disorders with non-Mendelian patterns of inheritance.
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Affiliation(s)
| | - KV Chowdari
- Department of Psychiatry, University of Pittsburgh School of Medicine
| | | | - Vishwajit L Nimgaonkar
- To whom correspondence should be addressed; Departments of Psychiatry and Human Genetics, University of Pittsburgh School of Medicine, and Graduate School of Public Health, Western Psychiatric Institute and Clinic, Room 441, 3811 O'Hara St., Pittsburgh, PA 15213; tel.: 412-246-6353, fax: 412-246-6350; e-mail:
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Hatfield JS. The genetic basis of hair whorl, handedness, and other phenotypes. Med Hypotheses 2006; 66:708-14. [PMID: 16337093 DOI: 10.1016/j.mehy.2005.10.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 10/06/2005] [Accepted: 10/07/2005] [Indexed: 11/20/2022]
Abstract
Evidence is presented that RHD, RHCE, and other RH genes, may be interesting candidates to consider when searching for the genetic basis of hair whorl rotation (i.e., clockwise or counterclockwise), handedness (i.e., right handed, left handed or ambidextrous), speech laterality (i.e., right brained or left brained), speech dyslexia (e.g., stuttering), sexual orientation (i.e., heterosexual, homosexual, bisexual, or transsexual), schizophrenia, bipolar disorder, and autism spectrum disorder. Such evidence involves the need for a genetic model that includes maternal immunization to explain some of the empirical results reported in the literature. The complex polymorphisms present among the maternally immunizing RH genes can then be used to explain other empirical results. Easily tested hypotheses are suggested, based upon genotypic (but not phenotypic) frequencies of the RH genes. In particular, homozygous dominant individuals are expected to be less common or lacking entirely among the alternative phenotypes. If it is proven that RH genes are involved in brain architecture, it will have a profound effect upon our understanding of the development and organization of the asymmetrical vertebrate brain and may eventually lead to a better understanding of the developmental processes which occur to produce the various alternative phenotypes discussed here. In addition, if RH genes are shown to be involved in the production of these phenotypes, then the evolutionary studies can be performed to demonstrate the beneficial effect of the recessive alleles of RHD and RHCE, and why human evolution appears to be selecting for the recessive alleles even though an increase in the frequency of such alleles may imply lower average fecundity among some individuals possessing them.
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Affiliation(s)
- Jeff S Hatfield
- USGS Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, MD 20708, USA.
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Abstract
It has become obvious from epidemiological studies in families of patients affected or from twin studies, that most psychiatric disorders are in part genetically determined. Genetics have raised incredible hopes that the complex nature of psychiatric disorders might be unravelled. However, progress in psychiatry genetics have met major difficulties that have hampered psychiatry taking advantage of the new technologies as compared to other fields, such as neurology. In this non-exhaustive review, we propose an overview from the initial evidence to the expected future, through a critical statement on the current situation.
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Affiliation(s)
- Marie-Odile Krebs
- INSERM E0117-Paris V, Université René Descartes, Paris; Hôpital Sainte-Anne, 7 Rue Cabanis, 75014 Paris, France.
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Thomson PA, Wray NR, Millar JK, Evans KL, Hellard SL, Condie A, Muir WJ, Blackwood DHR, Porteous DJ. Association between the TRAX/DISC locus and both bipolar disorder and schizophrenia in the Scottish population. Mol Psychiatry 2005; 10:657-68, 616. [PMID: 15838535 DOI: 10.1038/sj.mp.4001669] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Translin-associated factor X/Disrupted in Schizophrenia 1 (TRAX/DISC) region was first implicated as a susceptibility locus for schizophrenia by analysis of a large Scottish family in which a t(1;11) translocation cosegregates with schizophrenia, bipolar disorder and recurrent major depression. We now report evidence for association between bipolar disorder and schizophrenia and this locus in the general Scottish population. A systematic study of linkage disequilibrium in a representative sample of the Scottish population was undertaken across the 510 kb of TRAX and DISC1. SNPs representing each haplotype block were selected for case-control association studies of both schizophrenia and bipolar disorder. Significant association with bipolar disorder in women P=0.00026 (P=0.0016 in men and women combined) was detected in a region of DISC1. This same region also showed nominally significant association with schizophrenia in both men and women combined, P=0.0056. Two further regions, one in TRAX and the second in DISC1, showed weaker evidence for sex-specific associations of individual haplotypes with bipolar disorder in men and women respectively, P<0.01. Only the association between bipolar women and DISC1 remained significant after correction for multiple testing. This result provides further supporting evidence for DISC1 as a susceptibility factor for both bipolar disorder and schizophrenia, consistent with the diagnoses in the original Scottish translocation family.
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Affiliation(s)
- P A Thomson
- Medical Genetics Section, University of Edinburgh, Molecular Medicine Centre, Western General Hospital, Edinburgh, UK.
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McGrath J, Mowry B, Whiteford H. Queensland Centre for Mental Health Research: the first 17 years. Aust N Z J Psychiatry 2005; 39:533-41. [PMID: 15996133 DOI: 10.1080/j.1440-1614.2005.01624.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To reflect on the establishment and evolution of the Queensland Centre for Mental Health Research. METHOD Narrative historical review. RESULTS First established as an inpatient research unit in December 1987, the focus of the Centre evolved in concert with the skills of the staff. After the structure was revised in 1996 and 1999, the Centre has evolved into a group with four main research streams--epidemiology, developmental neurobiology, genetics and policy and economics. Although the group maintains a strong focus on serious mental disorders such as schizophrenia, our policy and economic work has a wider perspective. The Queensland Centre for Mental Health Research is based in an historic mental health service, with laboratories in collaborating universities and institutes. Key lessons learnt by the group along the way relate to the importance of focusing on a restricted range of research topics in order to build a critical mass. CONCLUSIONS Given a facilitating environment, hospital-based research groups can prosper. Over the last 17 years, a cost-efficient, focused and productive research group has evolved that has made contributions to international research.
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Affiliation(s)
- John McGrath
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health and Department of Psychiatry, University of Queensland, Brisbane, Queensland, Australia.
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Shanahan MJ, Hofer SM. Social context in gene-environment interactions: retrospect and prospect. J Gerontol B Psychol Sci Soc Sci 2005; 60 Spec No 1:65-76. [PMID: 15863711 DOI: 10.1093/geronb/60.special_issue_1.65] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
While many behavioral scientists believe that gene-environment (GE) interactions play an important and perhaps pervasive role in human development and aging, little attention has been devoted to a fundamental conceptual issue: What is it about social context that could alter gene expression? We draw on existing examples of GE interactions to formulate a typology that identifies a set of generic mechanisms by which E moderates G. Empirical studies suggest four ideal types: Social context can trigger a genetic diathesis, compensate for a genetic diathesis, act as a control to prevent behaviors for which there is a genetic predisposition, and enhance adaptation through proximal processes. This typology highlights several problems, however, with prior empirical research, which may explain, in part, why so few GE interactions have actually been observed. These problems include inattention to the dynamic nature of social experience, the manifold, often-intercorrelated dimensions of social context ("EE interactions"), mediators that link social context and the genotype, and analytic models that examine GE interactions as processes that characterize individual development. In turn, these insights call for the integration of life course sociology and behavioral genetics to foster ways of studying genes, context, and aging.
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Affiliation(s)
- Michael J Shanahan
- Department of Sociology, University of North Carolina, Chapel Hill, NC 27599-3210, USA.
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Abstract
The article reviews literature on methods for meta-analysis of genetic linkage and association studies, and summarizes and comments on specific meta-analysis findings for psychiatric disorders. The Genome Scan Meta-Analysis and Multiple Scan Probability methods assess the evidence for linkage across studies. Multiple Scan Probability analysis suggested linkage of two chromosomal regions (13q and 22q) to schizophrenia and bipolar disorder, whereas Genome Scan Meta-Analysis on a larger sample identified at least 10 schizophrenia linkage regions, but none for bipolar disorder. Meta-analyses of pooled ORs support association of schizophrenia to the Ser311Cys polymorphism in DRD2 and the T102C polymorphism in HTR2A, and of attention deficit hyperactivity disorder to the 48-bp repeat in DRD4. The 5-HTTLPR polymorphism in the serotonin transporter gene (SLC6A4) may contribute to the risk of bipolar disorder, suicidal behavior, and neuroticism, but association to the lifetime risk of major depression has not been shown. Meta-analyses support linkage of schizophrenia to regions where replicable associations to candidate genes have been identified through positional cloning methods. There are additional supported regions where susceptibility genes are likely to be identified. Linkage meta-analysis has had less clear success for bipolar disorder based on a smaller dataset. Meta-analysis can guide the prioritization of regions for study, but proof of association requires biological confirmation of hypotheses about gene actions. Elucidation of causal mechanisms will require more comprehensive study of sequence variation in candidate genes, better statistical and meta-analytic methods to take all variation into account, and biological strategies for testing etiologic hypotheses.
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Affiliation(s)
- Douglas F Levinson
- Department of Psychiatry, University of Pennsylvania School of Medicine, 3535 Market Street, Room 4006, Philadelphia, PA 19104, USA.
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Abstract
The causes of schizophrenia and bipolar human psychiatric disorders are unknown. A novel somatic cell genetic model postulated nonrandom segregation of "Watson" vs. "Crick" DNA chains of both copies of a chromosome to specific daughter cells. Such an oriented asymmetric cell division causes development of healthy, functionally nonequivalent brain hemispheres. Genetic translocations of the chromosome may cause disease by disrupting the biased strand-segregation process. Only one-half of chromosome 1 and 11 translocation carriers developing disease were recently explained as a result consistent with the model (Klar 2002). Is chromosome 1 or 11 involved? Does the translocation breakpoint cause disease? Remarkably, two other unrelated chromosome 11 translocations discovered from the literature likewise caused disease in approximately 50% of carriers. Together, their breakpoints lie at three distinct regions spanning approximately 40% of chromosome 11. Thus, chromosome 11 is implicated but the breakpoints themselves are unlikely to cause the disease. The results suggest that the genetically caused disease develops without a Mendelian gene mutation.
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Affiliation(s)
- Amar J S Klar
- Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute, Frederick, Maryland 21702-1201, USA.
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Macgregor S, Visscher PM, Knott SA, Thomson P, Porteous DJ, Millar JK, Devon RS, Blackwood D, Muir WJ. A genome scan and follow-up study identify a bipolar disorder susceptibility locus on chromosome 1q42. Mol Psychiatry 2004; 9:1083-90. [PMID: 15249933 DOI: 10.1038/sj.mp.4001544] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this study, we report a genome scan for psychiatric disease susceptibility loci in 13 Scottish families. We follow up one of the linkage peaks on chromosome 1q in a substantially larger sample of 22 families affected by schizophrenia (SCZ) or bipolar affective disorder (BPAD). To minimise the effect of genetic heterogeneity, we collected mainly large extended families (average family size >18). The families collected were Scottish, carried no chromosomal abnormalities and were unrelated to the large family previously reported as segregating a balanced (1:11) translocation with major psychiatric disease. In the genome scan, we found linkage peaks with logarithm of odds (LOD) scores >1.5 on chromosomes 1q (BPAD), 3p (SCZ), 8p (SCZ), 8q (BPAD), 9q (BPAD) and 19q (SCZ). In the follow-up sample, we obtained most evidence for linkage to 1q42 in bipolar families, with a maximum (parametric) LOD of 2.63 at D1S103. Multipoint variance components linkage gave a maximum LOD of 2.77 (overall maximum LOD 2.47 after correction for multiple tests), 12 cM from the previously identified SCZ susceptibility locus DISC1. Interestingly, there was negligible evidence for linkage to 1q42 in the SCZ families. These results, together with results from a number of other recent studies, stress the importance of the 1q42 region in susceptibility to both BPAD and SCZ.
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Affiliation(s)
- S Macgregor
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Kings Buildings, Edinburgh, UK.
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26
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Ekelund J, Hennah W, Hiekkalinna T, Parker A, Meyer J, Lönnqvist J, Peltonen L. Replication of 1q42 linkage in Finnish schizophrenia pedigrees. Mol Psychiatry 2004; 9:1037-41. [PMID: 15197400 DOI: 10.1038/sj.mp.4001536] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromosome 1q has been implicated in the etiology of schizophrenia in several independent studies. However, the peak linkage findings have been dispersed over a large chromosomal region, with negative findings in this region also being reported. Our group has previously observed linkage on chromosome 1q42, maximizing within the DISC1 gene, which has also been implied in the etiology of schizophrenia based on functional studies. In the study presented here, we genotyped 300 polymorphic markers on chromosome 1 using a study sample of 70 families with multiple individuals affected with schizophrenia or related conditions, independent of the study samples in our previous reports. We again found evidence for linkage on 1q42 maximizing within the DISC1 gene (rs1000731, lod=2.70). Further, a haplotype containing the most strongly linked markers showed some evidence of association with the disease. This replicates the previous linkage finding in the same region and constitutes supportive evidence for a susceptibility gene in this region.
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Affiliation(s)
- J Ekelund
- National Public Health Institute, Department of Molecular Medicine, Helsinki, Finland.
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Abstract
We are on the brink of exciting discoveries into the molecular genetic underpinnings of autism spectrum disorder. Overwhelming evidence of genetic involvement coupled with increased societal attention to the disorder has drawn in more researchers and more research funding. Autism is a strongly genetic yet strikingly complex disorder, in which evidence from different cases supports chromosomal disorders, rare single gene mutations, and multiplicative effects of common gene variants. With more and more interesting yet sometimes divergent findings emerging every year, it is tempting to view these initial molecular studies as so much noise, but the data have also started to coalesce in certain areas. In particular, recent studies in families with autism spectrum disorder have identified uncommon occurrences of a novel genetic syndrome caused by disruptions of the NLGN4 gene on chromosome Xp22. Previous work had identified another uncommon syndrome that is caused by maternal duplications of the chromosome 15q11-13 region. We highlight other converging findings, point toward those areas most likely to yield results, and emphasize the contributions of multiple approaches to identifying the genes of interest.
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Mowry BJ, Holmans PA, Pulver AE, Gejman PV, Riley B, Williams NM, Laurent C, Schwab SG, Wildenauer DB, Bauché S, Owen MJ, Wormley B, Sanders AR, Nestadt G, Liang KY, Duan J, Ribble R, Norton N, Soubigou S, Maier W, Ewen-White KR, DeMarchi N, Carpenter B, Walsh D, Williams H, Jay M, Albus M, Nertney DA, Papadimitriou G, O'Neill A, O'Donovan MC, Deleuze JF, Lerer FB, Dikeos D, Kendler KS, Mallet J, Silverman JM, Crowe RR, Levinson DF. Multicenter linkage study of schizophrenia loci on chromosome 22q. Mol Psychiatry 2004; 9:784-95. [PMID: 15007391 DOI: 10.1038/sj.mp.4001481] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hypothesis of the existence of one or more schizophrenia susceptibility loci on chromosome 22q is supported by reports of genetic linkage and association, meta-analyses of linkage, and the observation of elevated risk for psychosis in people with velocardiofacial syndrome, caused by 22q11 microdeletions. We tested this hypothesis by evaluating 10 microsatellite markers spanning 22q in a multicenter sample of 779 pedigrees. We also incorporated age at onset and sex into the analysis as covariates. No significant evidence for linkage to schizophrenia or for linkage associated with earlier age at onset, gender, or heterogeneity across sites was observed. We interpret these findings to mean that the population-wide effects of putative 22q schizophrenia susceptibility loci are too weak to detect with linkage analysis even in large samples.
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Affiliation(s)
- B J Mowry
- Queensland Centre for Mental Health Research, The Park -- Centre for Mental Health, Wacol, Queensland, Australia.
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Abstract
We are rapidly approaching the postgenomic era in which we will know all of the 3 billion DNA bases in the human genome sequence and all of the variations in the genome sequence that are ultimately responsible for genetic influence on behavior. These ongoing advances and new techniques will make it easier to identify genes associated with psychopathology. Progress in identifying such genes has been slower than some experts expected, probably because many genes are involved for each phenotype, which means the effect of any one gene is small. Nonetheless, replicated linkages and associations are being found, for example, for dementia, reading disability, and hyperactivity. The future of genetic research lies in finding out how genes work (functional genomics). It is important for the future of psychology that pathways between genes and behavior be examined at the top-down psychological level of analysis (behavioral genomics), as well as at the bottom-up molecular biological level of cells or the neuroscience level of the brain. DNA will revolutionize psychological research and treatment during the coming decades.
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Affiliation(s)
- Robert Plomin
- Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, King's College London, DeCrespigny Park, London SE5 8AF, UK.
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Rosa A, Peralta V, Papiol S, Cuesta MJ, Serrano F, Martínez-Larrea A, Fañanás L. Interleukin-1beta (IL-1beta) gene and increased risk for the depressive symptom-dimension in schizophrenia spectrum disorders. Am J Med Genet B Neuropsychiatr Genet 2004; 124B:10-4. [PMID: 14681906 DOI: 10.1002/ajmg.b.20074] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Interleukin-1beta (IL-1beta), as well as other cytokines, has been classically implicated in the pathophysiology of major psychiatric disorders such as schizophrenia and major depression, and recent studies have implicated the IL-1beta gene and schizophrenia. Nevertheless, new approaches to this complex phenotype are necessary to clarify the risk conferred by this gene, either to the disorder or to its clinical manifestations. The aim of the present study was to explore the effect of a genetic polymorphism of the promoter region of the IL-1beta gene, in schizophrenia defined with: (i) a categorical diagnosis and (ii) a multidimensional symptom approach. We studied 356 individuals from 89 nuclear families consisting of one affected individual and the unaffected father, mother, and sib, in a family-based association study design. We find a trend for biased transmission of allele 2 from heterozygous parents to affected offspring, categorically defined (P = 0.07). This tendency was not observed in the healthy offspring. Using a multidimensional symptom approach to the diagnosis, the association was confirmed in psychotic patients showing the depressive symptom-dimension (P = 0.02).
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Affiliation(s)
- Araceli Rosa
- Unitat d'Antropologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
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31
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Klar AJS. An epigenetic hypothesis for human brain laterality, handedness, and psychosis development. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 69:499-506. [PMID: 16117687 DOI: 10.1101/sqb.2004.69.499] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- A J S Klar
- Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute at Frederick, Frederick, Maryland 21702-1201, USA
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Abstract
The study of schizophrenia genetics has revealed much about the disease but none of the essential secrets of its etiology, so far, for numerous reasons. First, schizophrenia is a complex trait, influenced by both genes and environment. Second, it appears to be a highly heterogeneous disease, with locus and allelic heterogeneity both between and within families likely. Third, since it is common, it is likely that the genetic liability variants are common, and so are found with relatively high frequency in the general population. Fourth, linkage methods, which deliver rapid coverage of the genome, have great power to identify single genes causing Mendelian disorders but are poorly suited to the genetic architecture of complex traits. Although association methods are undeniably more powerful in such situations, affordable technologies to deliver the much higher density whole genome coverage required are not yet available and candidate gene studies of schizophrenia have not produced robust and replicable results. In spite of these limitations, there are now sufficient data to support several conclusions. Numerous regions of the human genome give consistent, though by no means unanimous, support for linkage. The precise nature of these signals is not yet understood, and power to position the effects is poor, but metanalyses show the co-occurrence is unlikely to be due to chance. Combined approaches utilizing linkage for rapid genome coverage and association for fine-scale follow-up have identified several promising candidate genes. Although the definition of replication in a complex trait is itself complex, a number of these candidates have been supported by numerous studies. These converging lines of evidence suggest that the genetics of schizophrenia, long considered a most intractable problem, are at last beginning to be unraveled.
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Affiliation(s)
- Brien Riley
- Departments of Psychiatry and Human Genetics, Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA.
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Nakamura A, Okazaki Y, Sugimoto J, Oda T, Jinno Y. Human endogenous retroviruses with transcriptional potential in the brain. J Hum Genet 2003; 48:575-81. [PMID: 14564540 DOI: 10.1007/s10038-003-0081-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 09/05/2003] [Indexed: 12/23/2022]
Abstract
Genetic studies of neuropsychiatric disorders have often produced conflicting results, which might partly result from the involvement of epigenetic modifications. We intended to explore the possible implication of DNA methylation and human endogenous retroviruses (HERVs) in neuropsychiatric disorders. In the present study, we identified two HERV loci that are expected to retain the transcriptional activity in the brain. One was located on chromosome 1q21-q22 and the other on 22q12. Interestingly, these regions were overlapped with or included in those of schizophrenia-susceptible loci, SCZD9 and SCZD4, respectively. Particularly, the HERV on 22q12 was located in the opposite direction 4 kb downstream of the Synapsin III gene. These HERV loci could afford clear targets for methylation and expression analyses in postmortem brains of patients with psychiatric disorders such as schizophrenia. In addition, we confirmed our previous finding that only a few of particular HERV-K loci were activated among a number of highly homologous loci in teratocarcinoma cell lines. These activated loci included ones common to all teratocarcinoma cell lines analyzed and depending on their male or female origin.
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Affiliation(s)
- Akifumi Nakamura
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Nishihara, Okinawa 903-0215, Japan
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36
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Abstract
Australian research in psychiatric genetics covers molecular genetic studies of depression, anxiety, alcohol dependence, Alzheimer's disease, bipolar disorder, schizophrenia, autism, and attention deficit hyperactivity disorder. For each disorder, a variety of clinical cohorts have been recruited including affected sib pair families, trios, case/controls, and twins from a large population-based twin registry. These studies are taking place both independently and in collaboration with international groups. Microarray studies now complement DNA investigations, while animal models are in development. An Australian government genome facility provides a high throughput genotyping and mutation detection service to the Australian scientific community, enhancing the contribution of Australian psychiatric genetics groups to gene discovery.
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Affiliation(s)
- Bryan J Mowry
- Department of Psychiatry, Queensland Centre for Schizophrenia Research, University of Queensland, The Park, Centre for Mental Health, Wacol, Queensland 4076, Australia. ,edu.au
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Glatt SJ, Faraone SV, Tsuang MT. CAG-repeat length in exon 1 of KCNN3 does not influence risk for schizophrenia or bipolar disorder: a meta-analysis of association studies. Am J Med Genet B Neuropsychiatr Genet 2003; 121B:14-20. [PMID: 12898569 DOI: 10.1002/ajmg.b.20048] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Schizophrenia and bipolar disorder both show some evidence for genetic anticipation. In addition, significant expansion of anonymous CAG repeats throughout the genome has been detected in both of these disorders. The gene KCNN3, which codes for a small/intermediate conductance, calcium-regulated potassium channel, contains a highly polymorphic CAG-repeat array in exon 1. Initial evidence for association of both schizophrenia and bipolar disorder with increased CAG-repeat length of KCNN3 has not been consistently replicated. In the present study, we performed several meta-analyses to evaluate the pooled evidence for association with CAG-repeat length of KCNN3 derived from case-control and family-based studies of both disorders. Each group of studies was analyzed under two models, including a test for direct association with repeat length, and a test for association with dichotomized repeat-length groups. No evidence for a linear relationship between disease risk and repeat length was observed, as all pooled odds ratios approximated 1.0. Results of dichotomized allele-group analyses were more variable, especially for schizophrenia, where case-control studies found a significant association with longer repeats but family-based studies implicated shorter alleles. The results of these meta-analyses demonstrate that the risks for both schizophrenia and bipolar disorder are largely, if not entirely, independent of CAG-repeat length in exon 1 of KCNN3. This study cannot exclude the possibility that some aspect of this polymorphism, such as repeat-length disparity in heterozygotes, influences risk for these disorders. Further, it remains unknown if this polymorphism, or one in linkage disequilibrium with it, contributes to some distinct feature of the disorder, such as symptom severity or anticipation.
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Affiliation(s)
- Stephen J Glatt
- Department of Psychiatry, Harvard Medical School at Massachusetts Mental Health Center, Boston, Massachusetts 02115, USA
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Initial genome-wide scan for linkage with schizophrenia in the Japanese Schizophrenia Sib-Pair Linkage Group (JSSLG) families. Am J Med Genet B Neuropsychiatr Genet 2003; 120B:22-8. [PMID: 12815734 DOI: 10.1002/ajmg.b.20022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To determine if there are common genes that contribute to the susceptibility for schizophrenia, first-stage genome-wide scan was carried out by genotyping 417 short-tandem repeat (STR) markers in 338 individuals from 130 families with 148 affected sib-pairs identified at 16 sites nationwide in Japan. Data was from the Japanese Schizophrenia Sib-pair Linkage Group (JSSLG), which is a multi-site collaborative study group established to create a national resource for genetic studies of schizophrenia in Japan. All subjects were Japanese, and the probands and their siblings had schizophrenia. Multipoint non-parametric linkage analysis and exclusion mapping were performed with GENEHUNTER software. Simulation studies suggested that in the absence of linkage we could expect one multipoint maximum LOD score (MLS) of 1.9 per genome scan. An MLS of 3.7 would be expected only once in every 20 genome scans and thus corresponds to a genome-wide significance of 0.05. No loci in the initial screen fulfilled the criteria for significant or suggestive evidence for linkage. Ten chromosomes (1, 2, 3, 4, 5, 8, 9, 14, 17, and 20) had at least one region with a nominal P value < 0.05. Susceptibility genes with lambdas of 3 and 2 were excluded from 98 and 70% of the genome, respectively. Our results suggest that common genes that contribute significantly to susceptibility for schizophrenia are unlikely to exist in the Japanese population.
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Abstract
Recent twin studies confirm that schizophrenia is highly heritable, but attempts to locate and identify genes have proved to be difficult. This is largely because major genes appear to be rare or nonexistent. Instead, genetic liability almost certainly results from the combined effects of multiple susceptibility loci and most studies have been under-equipped to detect such effects. Nevertheless, several regions of the genome have been implicated by more than one linkage study and chromosome 22q has been implicated by linkage and by studies of patients with microdeletions. Recent work attempting to refine regions of interest using linkage dysequilibrium mapping has identified four promising and novel "positional candidates;" they are neuregulin-1 on chromosome 8p-p21, G72 located at chromosome 13q34, dysbindin at 6p22.3, and proline dehydrogenase, which is a gene that maps to chromosome 22q11. In addition, there is renewed interest in a fifth gene, catechol-O-methyltransferase, also on chromosome 22q11.
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Affiliation(s)
- Peter McGuffin
- SGDP Research Centre, Institute of Psychiatry, King's College London, De Crepigny Park,London SE5 8AF, UK.
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40
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Abstract
Schizophrenia is a common and debilitating illness, characterized by chronic psychotic symptoms and psychosocial impairment that exact considerable human and economic costs. The literature in electronic databases as well as citations and major articles are reviewed with respect to the phenomenology, pathology, treatment, genetics and neurobiology of schizophrenia. Although studied extensively from a clinical, psychological, biological and genetic perspective, our expanding knowledge of schizophrenia provides only an incomplete understanding of this complex disorder. Recent advances in neuroscience have allowed the confirmation or refutation of earlier findings in schizophrenia, and permit useful comparisons between the different levels of organization from which the illness has been studied. Schizophrenia is defined as a clinical syndrome that may include a collection of diseases that share a common presentation. Genetic factors are the most important in the etiology of the disease, with unknown environmental factors potentially modulating the expression of symptoms. Schizophrenia is a complex genetic disorder in which many genes may be implicated, with the possibility of gene-gene interactions and a diversity of genetic causes in different families or populations. A neurodevelopmental rather than degenerative process has received more empirical support as a general explanation of the pathophysiology, although simple dichotomies are not particularly helpful in such a complicated disease. Structural brain changes are present in vivo and post-mortem, with both histopathological and imaging studies in overall agreement that the temporal and frontal lobes of the cerebral cortex are the most affected. Functional imaging, neuropsychological testing and clinical observation are also generally consistent in demonstrating deficits in cognitive ability that correlate with abnormalities in the areas of the brain with structural abnormalities. The dopamine and other neurotransmitter systems are certainly involved in the treatment or modulation of psychotic symptoms. These broad findings represent the distillation of a large body of disparate data, but firm and specific findings are sparse, and much about schizophrenia remains unknown.
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Affiliation(s)
- Albert Hung Choy Wong
- Centre for Addiction and Mental Health, 250 College Street, M5T 1R8, Toronto, Ont., Canada.
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Abstract
Genome-wide scans for linkage have provided one of the dominant approaches adopted by researchers in their efforts to identify genes responsible for the inherited component of type 2 diabetes susceptibility. Around 20 genome scans have now been completed, in a wide variety of populations. Integration of data from these diverse scans has proven far from trivial, but the contours of genome-wide linkage topography are steadily emerging from the fog of data. Identification of the calpain-10 gene as the probable basis for the chromosome 2q linkage seen in Mexican Americans has provided validation of this positional cloning approach. This report provides an update on recent type 2 diabetes genome scan data, focusing on several chromosomal regions where the evidence for linkage has considerably strengthened in the past year. The current and future value of genome-wide linkage information in the search for type 2 diabetes susceptibility effects is also discussed.
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Affiliation(s)
- Mark I McCarthy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.
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Millar JK, Thomson PA, Wray NR, Muir WJ, Blackwood DHR, Porteous DJ. Response to Amar J. Klar: The chromosome 1;11 translocation provides the best evidence supporting genetic etiology for schizophrenia and bipolar affective disorders. Genetics 2003; 163:833-5; author reply 837-8. [PMID: 12645576 PMCID: PMC1462459 DOI: 10.1093/genetics/163.2.833] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Klar AJS. Response to Millar et al. Critique of Chromosome 1;11 Translocation Causing Psychosis. Genetics 2003. [DOI: 10.1093/genetics/163.2.837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Amar J S Klar
- Gene Regulation and Chromosome Laboratory, National Cancer Institute, Frederick, Maryland 21702
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Porteous DJ, Evans KL, Millar JK, Pickard BS, Thomson PA, James R, MacGregor S, Wray NR, Visscher PM, Muir WJ, Blackwood DH. Genetics of schizophrenia and bipolar affective disorder: strategies to identify candidate genes. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2003; 68:383-94. [PMID: 15338640 DOI: 10.1101/sqb.2003.68.383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Affiliation(s)
- D J Porteous
- Medical Genetics Section, University of Edinburgh, Western General Hospital, Edinburgh, Scotland, EH4 2XU
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Macgregor S, Visscher PM, Knott S, Porteous D, Muir W, Millar K, Blackwood D. Is Schizophrenia Linked to Chromosome 1q? Science 2002. [DOI: 10.1126/science.1075331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Stuart Macgregor
- Institute of Cell, Animal and Population Biology
Ashworth Laboratory
University of Edinburgh
West Mains Road
Edinburgh, EH9 3JT, UK
E-mail:
| | | | | | - David Porteous
- Department of Medical Genetics
Molecular Medicine Centre
University of Edinburgh
Crewe Road
Edinburgh, EH4 2XU, UK
| | - Walter Muir
- Department of Psychiatry
Kennedy Tower
University of Edinburgh
Morningside Park
Edinburgh, EH10 5HF, UK
| | - Kirsty Millar
- Department of Medical Genetics, Molecular Medicine Centre
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Merikangas KR, Chakravarti A, Moldin SO, Araj H, Blangero JC, Burmeister M, Crabbe J, Depaulo JR, Foulks E, Freimer NB, Koretz DS, Lichtenstein W, Mignot E, Reiss AL, Risch NJ, Takahashi JS. Future of genetics of mood disorders research. Biol Psychiatry 2002; 52:457-77. [PMID: 12361664 DOI: 10.1016/s0006-3223(02)01471-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This report summarizes the deliberations of a panel with representation from diverse disciplines of relevance to the genetics of mood disorders. The major charge to the panel was to develop a strategic plan to employ the tools of genetics to advance the understanding, treatment, and outcomes for mood disorders. A comprehensive review of the evidence for the role of genetic factors in the etiology of mood disorders was conducted, and the chief impediments for progress in gene identification were identified. The National Institute of Mental Health (NIMH) portfolios in the Genetics Research Branch and the Division of Mental Disorders, Behavioral Sciences, AIDS, and all genetics training activities were reviewed. Despite some promising leads, there are still no confirmed linkage findings for mood disorders. Impediments to gene finding include the lack of phenotypic validity, variation in ascertainment sources and methodology across studies, and genetic complexity. With respect to linkage, the committee recommended that a large-scale, integrated effort be undertaken to examine existing data from linkage and association studies of bipolar disorders using identical phenotypes and statistical methods across studies to determine whether the suggestive linkage findings at some loci can be confirmed. Confirmation would justify more intensive approaches to gene finding. The committee recommended that the NIMH support continued efforts to identify the most heritable subtypes and endophenotypes of major depression using the tools of genetic epidemiology, neuroscience, and behavioral science. The field of genetic epidemiology was identified as an important future direction because population-based, epidemiologic studies of families and unrelated affected individuals assume increasing importance for common chronic diseases. To prepare for shifts to more complex genetic models, the committee recommended that the NIMH develop new interdisciplinary training strategies to prepare for the next generation of genetics research.
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Affiliation(s)
- Kathleen R Merikangas
- National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
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Moises HW, Zoega T, Gottesman II. The glial growth factors deficiency and synaptic destabilization hypothesis of schizophrenia. BMC Psychiatry 2002; 2:8. [PMID: 12095426 PMCID: PMC117774 DOI: 10.1186/1471-244x-2-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2002] [Accepted: 07/03/2002] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND A systems approach to understanding the etiology of schizophrenia requires a theory which is able to integrate genetic as well as neurodevelopmental factors. PRESENTATION OF THE HYPOTHESIS Based on a co-localization of loci approach and a large amount of circumstantial evidence, we here propose that a functional deficiency of glial growth factors and of growth factors produced by glial cells are among the distal causes in the genotype-to-phenotype chain leading to the development of schizophrenia. These factors include neuregulin, insulin-like growth factor I, insulin, epidermal growth factor, neurotrophic growth factors, erbB receptors, phosphatidylinositol-3 kinase, growth arrest specific genes, neuritin, tumor necrosis factor alpha, glutamate, NMDA and cholinergic receptors. A genetically and epigenetically determined low baseline of glial growth factor signaling and synaptic strength is expected to increase the vulnerability for additional reductions (e.g., by viruses such as HHV-6 and JC virus infecting glial cells). This should lead to a weakening of the positive feedback loop between the presynaptic neuron and its targets, and below a certain threshold to synaptic destabilization and schizophrenia. TESTING THE HYPOTHESIS Supported by informed conjectures and empirical facts, the hypothesis makes an attractive case for a large number of further investigations. IMPLICATIONS OF THE HYPOTHESIS The hypothesis suggests glial cells as the locus of the genes-environment interactions in schizophrenia, with glial asthenia as an important factor for the genetic liability to the disorder, and an increase of prolactin and/or insulin as possible working mechanisms of traditional and atypical neuroleptic treatments.
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Affiliation(s)
- Hans W Moises
- Molecular Genetics Laboratory, Department of Psychiatry, Kiel University Hospital, Niemannsweg 147, 24105 Kiel, Germany
| | - Tomas Zoega
- Department of Psychiatry, National University of Iceland, Reykjavik, Iceland
| | - Irving I Gottesman
- Departments of Psychiatry and Psychology, University of Minnesota, Minneapolis, USA
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Citver AS, Shields AM, Ciaccia LM, Schulingkamp RJ, Raffa RB. Indirect modulation of dopamine D2 receptors as potential pharmacotherapy for schizophrenia: III. Retinoids. J Clin Pharm Ther 2002; 27:161-8. [PMID: 12081629 DOI: 10.1046/j.1365-2710.2002.00410.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Present antipsychotic drugs, whose clinical activity correlates with direct binding to dopamine D2 or other receptors, alleviate some of the symptoms of schizophrenia, but not all and not completely in many patients. In continuation of our overview of potential novel antipsychotic pharmacotherapy that would be based upon indirect modulation of dopamine or other neurotransmitter functioning, we focus in this article on the postulated use of retinoid analogs as novel antipsychotic agents. Several lines of evidence can be viewed as implicating retinoid dysregulation in schizophrenia, either as a causative or contributory factor. It has been proposed that using retinoid analogs to alter the downstream expression of dopamine D2 receptors might represent a novel approach to the treatment of the disease or amelioration of symptoms when used either as monotherapy or as adjunct pharmacotherapy to dopamine D2 receptor antagonists.
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Abstract
Schizophrenia is a debilitating mental illness that affects 1% of the population. Despite intensive study, its molecular etiology remains enigmatic. Like many common diseases, schizophrenia is multifactorial in origin, with both genetic and environmental contributions likely playing an important role in the manifestation of symptoms. Recent advances based on pharmacological studies, brain imaging analyses, and genetic research are now converging on tantalizing leads that point to a central role for several neurotransmitters, including dopamine, glutamate, and serotonin, that may interface with neurodevelopmental defects reflecting disease-related genetic aberrations. Here, we provide a brief overview of the parallel approaches being used to identify the molecular causes of schizophrenia and discuss possible directions for future research.
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Affiliation(s)
- Akira Sawa
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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