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Trifu SC, Kohn B, Vlasie A, Patrichi BE. Genetics of schizophrenia (Review). Exp Ther Med 2020; 20:3462-3468. [PMID: 32905096 PMCID: PMC7465115 DOI: 10.3892/etm.2020.8973] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 06/30/2020] [Indexed: 12/14/2022] Open
Abstract
A comprehensive review of the body of genetic studies on schizophrenia seems even more daunting than the battle a psychiatrist wages daily in the office with her archenemy of a thousand faces. The following article reunites some genetic, epigenetic and environmental factors of schizophrenia from revered and vast studies in a chronological and progressive fashion. Twin studies set the basics of heritability and a particular study by Davis and Phelps considers the widely ignored influence of prenatal environment in the development of schizophrenia. Mostly ignited by linkage studies, candidate gene studies explore further by fine-mapping the hypothesized variants [mostly in the forms single nucleotide polymorphisms (SNPs) and less but with greater impact copy number variations (CNVs)] associated with the disease. Genome-wide association studies (GWAS) increase considerably the sample sizes and thus the validity of the results, while the next-generation sequencing (NGS) attain the highest yet unreplicated level of validity results.
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Affiliation(s)
- Simona Corina Trifu
- Department of Neurosciences, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Bianca Kohn
- Department of Psychiatry, ‘Prof. Dr. Alexandru Obregia’ Clinical Hospital of Psychiatry, 041914 Bucharest, Romania
| | - Andrei Vlasie
- Department of Psychiatry, ‘Prof. Dr. Alexandru Obregia’ Clinical Hospital of Psychiatry, 041914 Bucharest, Romania
| | - Bogdan-Eduard Patrichi
- Department of Psychiatry and Psychology, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
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LE L, R K, B M, Mj G. Risk of schizophrenia in relatives of individuals affected by schizophrenia: A meta-analysis. Psychiatry Res 2020; 286:112852. [PMID: 32065982 DOI: 10.1016/j.psychres.2020.112852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 12/31/2022]
Abstract
A meta-analysis was conducted to estimate schizophrenia incidence in first-degree relatives (FDRs) of probands diagnosed with schizophrenia. The aim was to inform future schizophrenia research and improve accuracy of risk communication to patients. Schizophrenia risk in FDRs with 1 or 2 probands with schizophrenia was investigated by conducting a systematic review of cohort and case-control studies with the following criteria: published between 1977 and 2018; reported odds ratios (OR), relative risk (RR) or sufficient raw data to calculate OR or RR; used appropriate diagnostic criteria; and reported systematic proband recruitment and ascertainment of relatives. Studies were obtained via EMBASE and MEDLINE electronic database searches. From an initial 5755 articles, 19 met the inclusion criteria. Mean effect sizes across studies were estimated using random effects methods. Estimates for schizophrenia risk were OR = 7.69 (95% CI 5.11-11.56) for FDRs of one proband with schizophrenia compared to healthy control probands, increasing to OR = 11.11 (95% CI = 1.45-85.02) for FDRs with two probands with schizophrenia. These findings support the existing literature suggesting significant genetic liability for schizophrenia. The results can be used to educate individuals with a family history of schizophrenia about their risk.
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Affiliation(s)
- Lo LE
- Psychosocial Research Group, Prince of Wales Clinical School, Sydney, NSW, Australia
| | - Kaur R
- Psychosocial Research Group, Prince of Wales Clinical School, Sydney, NSW, Australia
| | - Meiser B
- Psychosocial Research Group, Prince of Wales Clinical School, Sydney, NSW, Australia.
| | - Green Mj
- School of Psychiatry, University of New South Wales, NSW 2052, Australia; Neuroscience Research Australia, Sydney, NSW 2031, Australia
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Crawford L, Loprinzi PD. Effects of Exercise on Memory Interference in Neuropsychiatric Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1228:425-438. [PMID: 32342475 DOI: 10.1007/978-981-15-1792-1_29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
There are several mechanisms that cause memory impairment, including motivated forgetting, active forgetting, natural decay, and memory interference. Interference occurs when one is attempting to recall something specific, but there is conflicting information making it more difficult to recall the target stimuli. In laboratory settings, it is common to measure memory interference with paired associate tasks-usually utilizing the AB-CD, AB-AC, AB-ABr, or AB-DE AC-FG method. Memory impairments are frequent among those with neuropsychiatric disorders such as depression, schizophrenia, and multiple sclerosis. The memory effects of each condition differ, but are all related to alterations in brain physiology and general memory deterioration. Exercise, or physical activity, has been demonstrated to attenuate memory interference in some cases, but the mechanisms are still being determined. Further research is needed on memory interference, in regard to exercise and neuropsychiatric disorders.
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Affiliation(s)
- Lindsay Crawford
- Department of Health, Exercise Science, and Recreation Management, Exercise and Memory Laboratory, The University of Mississippi, MS, Oxford, USA
| | - Paul D Loprinzi
- Department of Health, Exercise Science, and Recreation Management, Exercise and Memory Laboratory, The University of Mississippi, MS, Oxford, USA.
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Mohamed ZI, Tee SF, Chow TJ, Loh SY, Yong HS, Bakar AKA, Tang PY. Functional characterization of two variants in the 3'-untranslated region (UTR) of transcription factor 4 gene and their association with schizophrenia in sib-pairs from multiplex families. Asian J Psychiatr 2019; 40:76-81. [PMID: 30771755 DOI: 10.1016/j.ajp.2019.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/30/2019] [Accepted: 02/07/2019] [Indexed: 12/12/2022]
Abstract
Transcription factor 4 (TCF4) gene plays an important role in nervous system development and it always associated with the risk of schizophrenia. Since miRNAs regulate targetgenes by binding to 3'UTRs of target mRNAs, the functional variants located in 3'UTR of TCF4 are highly suggested to affect the gene expressions in schizophrenia. To test the hypothesis regarding the effects of the variants located in 3'UTR of TCF4, we conducted an in silico analysis to identify the functional variants and their predicted functions. In this study, we sequenced the 3'UTR of TCF4 in 13 multiplex schizophrenia families and 14 control families. We found two functional variants carried by three unrelated patients. We determined that the C allele of rs1272363 and the TC insert of rs373174214 might suppress post- transcriptional expression. Secondly, we cloned the region that flanked these two variants into a dual luciferase reporter system and compared the luciferase activities between the pmirGLO-TCF4 (control), pmirGLO-TCF4-rs373174214 and pmirGLO-TCF4-rs1273263. Both pmirGLO-TCF4-rs373174214 and pmirGLO-TCF4-rs1273263 caused lower reporter gene activities, as compared to the control. However, only the C allele of rs1272363 reduced the luciferase activity significantly (p = 0.0231). Our results suggested that rs1273263 is a potential regulator of TCF4 expression, and might be associated with schizophrenia.
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Affiliation(s)
- Zahra Isnaini Mohamed
- Department of Mechatronics and Biomedical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Bandar Sungai Long, Cheras 43000 Kajang, Malaysia
| | - Shiau Foon Tee
- Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Bandar Sungai Long, Cheras 43000 Kajang, Malaysia
| | - Tze Jen Chow
- Department of Mechatronics and Biomedical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Bandar Sungai Long, Cheras 43000 Kajang, Malaysia
| | - Siew Yim Loh
- Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Hoi Sen Yong
- Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | - Pek Yee Tang
- Department of Mechatronics and Biomedical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Bandar Sungai Long, Cheras 43000 Kajang, Malaysia.
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Thorup AAE, Hemager N, Søndergaard A, Gregersen M, Prøsch ÅK, Krantz MF, Brandt JM, Carmichael L, Melau M, Ellersgaard DV, Burton BK, Greve AN, Uddin MJ, Ohland J, Nejad AB, Johnsen LK, Ver Loren van Themaat AH, Andreassen AK, Vedum L, Knudsen CB, Stadsgaard H, M. Jepsen JR, Siebner HR, Østergaard L, Bliksted VF, Plessen KJ, Mors O, Nordentoft M. The Danish High Risk and Resilience Study-VIA 11: Study Protocol for the First Follow-Up of the VIA 7 Cohort -522 Children Born to Parents With Schizophrenia Spectrum Disorders or Bipolar Disorder and Controls Being Re-examined for the First Time at Age 11. Front Psychiatry 2018; 9:661. [PMID: 30631284 PMCID: PMC6315161 DOI: 10.3389/fpsyt.2018.00661] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
Introduction: Offspring of parents with severe mental illness have an increased risk of developing mental illnesses themselves. Familial high risk cohorts give a unique opportunity for studying the development over time, both the illness that the individual is predisposed for and any other diagnoses. These studies can also increase our knowledge of etiology of severe mental illness and provide knowledge about the underlying mechanisms before illness develops. Interventions targeting this group are often proposed due to the potential possibility of prevention, but evidence about timing and content is lacking. Method: A large, representative cohort of 522 7-year old children born to parents with schizophrenia, bipolar disorder or controls was established based on Danish registers. A comprehensive baseline assessment including neurocognition, motor functioning, psychopathology, home environment, sociodemographic data, and genetic information was conducted from January 1, 2013 to January 31, 2016. This study is the first follow-up of the cohort, carried out when the children turn 11 years of age. By assessing the cohort at this age, we will evaluate the children twice before puberty. All instruments have been selected with a longitudinal perspective and most of them are identical to those used at inclusion into the study at age 7. A diagnostic interview, motor tests, and a large cognitive battery are conducted along with home visits and information from teachers. This time we examine the children's brains by magnetic resonance scans and electroencephalograms. Measures of physical activity and sleep are captured by a chip placed on the body, while we obtain biological assays by collecting blood samples from the children. Discussion: Findings from the VIA 7 study revealed large variations across domains between children born to parents with schizophrenia, bipolar and controls, respectively. This study will further determine whether the children at familial risk reveal delayed developmental courses, but catch up at age 11, or whether the discrepancies between the groups have grown even larger. We will compare subgroups within each of the familial high risk groups in order to investigate aspects of resilience. Data on brain structure and physical parameters will add a neurobiological dimension to the study.
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Affiliation(s)
- Anne A. E. Thorup
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Nicoline Hemager
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Anne Søndergaard
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Maja Gregersen
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Åsa Kremer Prøsch
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Mette F. Krantz
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Julie M. Brandt
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Line Carmichael
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Marianne Melau
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Ditte V. Ellersgaard
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte K. Burton
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
| | - Aja N. Greve
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Md Jamal Uddin
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Jessica Ohland
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
| | - Ayna B. Nejad
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Danish Research Centre for Magnetic Resonance, Section 714, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Line K. Johnsen
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Danish Research Centre for Magnetic Resonance, Section 714, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Anna Hester Ver Loren van Themaat
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Danish Research Centre for Magnetic Resonance, Section 714, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Anna K. Andreassen
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Lotte Vedum
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Christina B. Knudsen
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Henriette Stadsgaard
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Jens Richardt M. Jepsen
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Section 714, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Aarhus University, Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - Vibeke F. Bliksted
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
- Center of Functionally Integrative Neuroscience, Aarhus University, Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - Kerstin J. Plessen
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Research Unit, Child and Adolescent Mental Health Center, University of Copenhagen, Copenhagen, Denmark
- Division of Adolescent and Child Psychiatry, Department of Psychiatry, Lausanne University Hospital, Lausanne, Switzerland
| | - Ole Mors
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Merete Nordentoft
- The Lundbeck Foundation Intiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
- Mental Health Center Copenhagen, Research Unit, University of Copenhagen, Copenhagen, Denmark
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Muntaner C, Eaton WW, Diala CC. Social Inequalities in Mental Health: A Review of Concepts and Underlying Assumptions. Health (London) 2016. [DOI: 10.1177/136345930000400105] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We provide an overview of two major theoretical subjects in the study of the relation between social inequalities and mental health in the last 50 years: the conceptualization of social inequalities, and assumptions about their causes. The two conceptual approaches to the conceptualization of social inequalities are: 1) ‘social stratification’ or the ordering of individuals according to economic, political, or cultural rankings; and 2) ‘social class’ relations that yield a set of class positions for individuals according to their control over different types of assets (economic, political, cultural). The two major assumptions underlying these conceptual choices in studies of social inequalities and mental health are: 1) whether effects on mental health originate at the individual or at the group level (i.e. the ‘levels-of-analysis’ issue); and 2) whether mental health is the consequence of environmental determination or the individual’s capacity for making independent decisions (the ‘agency’ issue). We propose a typology of models of social inequalities in mental health that relates these levels-of-analysis and agency issues. The typology provides an efficient conceptual reorganization that uncovers the assumptions and policy implications of research on social inequalities in mental health.
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Affiliation(s)
| | | | - Chamberlain C. Diala
- University of Maryland & The Johns Hopkins University School of Hygiene and Public Health, USA
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New discoveries in schizophrenia genetics reveal neurobiological pathways: A review of recent findings. Eur J Med Genet 2015; 58:704-14. [PMID: 26493318 DOI: 10.1016/j.ejmg.2015.10.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 02/08/2023]
Abstract
Schizophrenia research has undergone a recent transformation. By leveraging large sample sizes, genome-wide association studies of common genetic variants have approximately tripled the number of candidate genetic loci. Rare variant studies have identified copy number variants that are schizophrenia risk loci. Among these, the 3q29 microdeletion is now known to be the single largest schizophrenia risk factor. Next-generation sequencing studies are increasingly used for rare variant association testing, and have already facilitated identification of large effect alleles. Collectively, recent findings implicate voltage-gated calcium channel and cytoskeletal pathways in the pathogenesis of schizophrenia. Taken together, these results suggest the possibility of imminent breakthroughs in the molecular understanding of schizophrenia.
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McTigue O, O’Callaghan E. Season of Birth as a Risk Factor. INTERNATIONAL JOURNAL OF MENTAL HEALTH 2015. [DOI: 10.1080/00207411.2000.11449497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Wei J, Hammings G. Allelic association between dinucleotide repeats at the monoamine oxidase loci and schizophrenia. Eur Psychiatry 2012; 13:407-10. [PMID: 19698656 DOI: 10.1016/s0924-9338(99)80687-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/1998] [Revised: 08/10/1998] [Accepted: 08/10/1998] [Indexed: 10/17/2022] Open
Abstract
Two X-linked microsatellites, (AC)n repeats at the monoamine oxidase (MAO) A locus and (TG)n repeats at the MAO-B locus, were typed by using a PCR-based procedure in 89 nuclear families consisting of mothers, fathers and female affected offspring with schizophrenia or mothers and male affected offspring. A haplotype-based haplotype relative risk (HHRR) approach was applied to detect allelic association of these two microsatellites with schizophrenia. In the families of male patients, a significant difference in frequency distribution was found between transmitted and non-transmitted (TG)n repeats (chi(2) = 15.13, df = 6, P = 0.019), and Fisher's exact test showed that allelic frequency of the transmitted (TG)(24) was significantly higher than that of the non-transmitted (TG)(24) (Fisher's P = 0.003). However, no significant differences in frequency distribution between mother- or father-transmitted and non-transmitted (TG)n repeats were found in the families of female patients. No significant differences in frequency distribution were found between transmitted and non-transmitted (AC)n repeats in the families of either male patients or female patients. The present study suggests that the MAO-B gene may be associated with schizophrenia, and the underlying genetic mechanism of schizophrenia may differ between male and female schizophrenic individuals.
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Mulle JG. Schizophrenia genetics: progress, at last. Curr Opin Genet Dev 2012; 22:238-44. [DOI: 10.1016/j.gde.2012.02.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 02/14/2012] [Accepted: 02/15/2012] [Indexed: 12/15/2022]
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Svensson AC, Lichtenstein P, Sandin S, Öberg S, Sullivan PF, Hultman CM. Familial aggregation of schizophrenia: the moderating effect of age at onset, parental immigration, paternal age and season of birth. Scand J Public Health 2011; 40:43-50. [PMID: 21930618 DOI: 10.1177/1403494811420485] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIMS An abundance of evidence has firmly established the familial aggregation of schizophrenia. The aim of this study was to examine how age at onset, parental characteristics and season of birth modify the familiality in schizophrenia. METHODS A population-based cohort was created by linking the Swedish Multi-Generation and Hospital Discharge Registers. Among 5,075,998 full siblings born between 1932 through to 1990, 16,346 cases of schizophrenia were identified. Familial aggregation was measured by the sibling recurrence-risk ratio, defined as the risk of schizophrenia among full siblings of schizophrenia patients compared with the risk among siblings of unaffected people. RESULTS We found a statistically significantly lower recurrence-risk ratio in siblings of later onset cases (7.2; 95% confidence interval (95% CI) 6.7-7.9) than of early onset cases (10.8; 95% CI 9.4-12.2). A lower recurrence-risk ratio was observed among offspring to fathers above 40 years (6.3; 95% CI 5.3-7.3) as compared with offspring of younger fathers (8.6; 95% CI 8.0-9.3). Further, among offspring to parents born outside Sweden the recurrence-risk ratio was statistically significantly lower (maternal immigrants 4.8; 95% CI 4.0-5.7, paternal immigrants 5.7; 95% CI 4.6-6.9) than among offspring to parents born in Sweden. CONCLUSIONS The familial aggregation of schizophrenia was reduced by higher age at onset, advancing paternal age and immigrant status of parents.
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Affiliation(s)
- Anna C Svensson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
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van Os J, Rutten BPF, Poulton R. Gene-environment interactions in schizophrenia: review of epidemiological findings and future directions. Schizophr Bull 2008; 34:1066-82. [PMID: 18791076 PMCID: PMC2632485 DOI: 10.1093/schbul/sbn117] [Citation(s) in RCA: 411] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Concern is building about high rates of schizophrenia in large cities, and among immigrants, cannabis users, and traumatized individuals, some of which likely reflects the causal influence of environmental exposures. This, in combination with very slow progress in the area of molecular genetics, has generated interest in more complicated models of schizophrenia etiology that explicitly posit gene-environment interactions (EU-GEI. European Network of Schizophrenia Networks for the Study of Gene Environment Interactions. Schizophrenia aetiology: do gene-environment interactions hold the key? [published online ahead of print April 25, 2008] Schizophr Res; S0920-9964(08) 00170-9). Although findings of epidemiological gene-environment interaction (G x E) studies are suggestive of widespread gene-environment interactions in the etiology of schizophrenia, numerous challenges remain. For example, attempts to identify gene-environment interactions cannot be equated with molecular genetic studies with a few putative environmental variables "thrown in": G x E is a multidisciplinary exercise involving epidemiology, psychology, psychiatry, neuroscience, neuroimaging, pharmacology, biostatistics, and genetics. Epidemiological G x E studies using indirect measures of genetic risk in genetically sensitive designs have the advantage that they are able to model the net, albeit nonspecific, genetic load. In studies using direct molecular measures of genetic variation, a hypothesis-driven approach postulating synergistic effects between genes and environment impacting on a final common pathway, such as "sensitization" of mesolimbic dopamine neurotransmission, while simplistic, may provide initial focus and protection against the numerous false-positive and false-negative results that these investigations engender. Experimental ecogenetic approaches with randomized assignment may help to overcome some of the limitations of observational studies and allow for the additional elucidation of underlying mechanisms using a combination of functional enviromics and functional genomics.
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Affiliation(s)
- Jim van Os
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University Medical Centre, EURON, SEARCH, Maastricht, The Netherlands.
| | - Bart PF Rutten
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University Medical Centre, EURON, SEARCH, PO Box 616 (location DOT 10), Maastricht, 6200 MD, The Netherlands
| | - Richie Poulton
- Dunedin Multidisciplinary Health and Development Research Unit, Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, PO Box 913, Dunedin, New Zealand
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13
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Traitement médicamenteux des schizophrénies à début précoce. Presse Med 2008; 37:853-8. [DOI: 10.1016/j.lpm.2008.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 01/02/2008] [Indexed: 11/17/2022] Open
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14
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Jordaan E, Niehaus DJH, Koen L, Seller C, Mbanga I, Emsley RA. Season of birth, age and negative symptoms in a Xhosa schizophrenia sample from the Southern Hemisphere. Aust N Z J Psychiatry 2006; 40:698-703. [PMID: 16866766 DOI: 10.1080/j.1440-1614.2006.01870.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Seasonality of birth, more specifically winter/spring births, has been implicated as a risk factor for the development of schizophrenia. The primary aim of this study was to determine whether schizophrenia patients of Xhosa ethnicity born in autumn/winter have different symptom profiles to those born in spring/summer. The secondary aim was to determine whether the autumn/winter and spring/summer birth rates for schizophrenia patients of Xhosa ethnicity were similar to that of the general Xhosa population. METHOD Individuals with a diagnosis of schizophrenia, born in the Western and Eastern Cape Provinces of South Africa (n = 386), were categorized as autumn/winter-born (March to August) patients or summer/spring-born (September to February) patients. Negative global scores of the schedules for the assessment of negative symptoms were categorized as normal (rating of 0 and 1) or positive (rating of 2 to 5). RESULTS Patients born in autumn/winter were more likely to have avolition/apathy than those born in summer/spring. The results also showed that the age of the patients played a significant role in modifying the effect of the season of birth on symptoms of schizophrenia. Especially older people (more than 30 years old) born in autumn/winter had a higher incidence of avolition/apathy than those born in summer/spring (p = 0.026). Furthermore, in the relationship of birth season and avolition/apathy, the marital status of the patient was a significant independent explanatory variable, while gender was not. The study also showed a spring excess of 4% in birth rate compared with the general Xhosa population. CONCLUSION The results from our study support the existence of a seasonal birth pattern in an African schizophrenia population and suggest that avolition/apathy may underpin this seasonal pattern.
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Affiliation(s)
- Esmè Jordaan
- MRC Biostatistics Unit, Bellville 7500, South Africa.
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15
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Wei J, Hemmings GP. A further study of a possible locus for schizophrenia on the X chromosome. Biochem Biophys Res Commun 2006; 344:1241-5. [PMID: 16650384 DOI: 10.1016/j.bbrc.2006.04.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
Several studies suggest that the X chromosome may contain a gene for schizophrenia. In the present study, we recruited 142 male schizophrenic patients and their biological mothers from all parts of the United Kingdom to detect a genetic association for the SYP/CACNA1F locus in the Xp11 region and the FACL4 locus in the Xq22.3-Xq23 region. The haplotype-based haplotype relative risk (HHRR) analysis showed allelic association for rs2071316 (chi2=6.85, P=0.009) and rs5905724 (chi2=5.3, P=0.021) at the CACNA1F locus, but not for rs5943414 and rs1324805 at the FACL4 locus and rs3817678 at the SYP locus. The haplotype analysis showed a weak association for the rs3817678-rs2071316-rs5905724 haplotypes (chi2=12.19, df=4, P=0.016) but did not show such an association for the rs5943414-rs1324805 haplotypes (chi2=3.96, df=2, P=0.138). Because the linkage disequilibrium signal was detected only at the CACNA1F locus, this gene should perhaps be considered as being a candidate for schizophrenia although further work is needed to draw firm conclusions.
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Affiliation(s)
- Jun Wei
- Institute of Biological Psychiatry, Schizophrenia Association of Great Britain, Bangor, Gwynedd LL57 2AG, UK.
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Bonnot O, Mazet P. Vulnérabilité aux schizophrénies à l'adolescence : revue de la littérature et applications cliniques. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.neurenf.2005.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Suvisaari JM, Haukka JK, Lönnqvist JK. No association between season of birth of patients with schizophrenia and risk of schizophrenia among their siblings. Schizophr Res 2004; 66:1-6. [PMID: 14693347 DOI: 10.1016/s0920-9964(02)00506-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Previous studies on the relationship between the season of birth of patients with schizophrenia and the risk of schizophrenia among their siblings have yielded contradictory results. We investigated whether proband's month of birth affects siblings' risk of developing schizophrenia. We used the Finnish Hospital Discharge Register to identify all patients born in Finland from 1950 to 1976 who had been hospitalized because of schizophrenia at least once between 1969 and 1995. Their siblings were identified from the National Population Register, and data on siblings were linked to the Hospital Discharge Register to obtain information on any hospitalizations. We used logistic regression to investigate a sibling's probability of developing schizophrenia, defining the proband initially as the first sibling in calendar time to develop schizophrenia, then as the affected sibling with lowest onset age. Within-family dependence was taken into account by using robust standard error estimates. Neither models found any association between proband's month of birth and siblings' odds of developing schizophrenia. Our results support those previous studies that found no association between proband's month of birth and family history of schizophrenia, and suggest that the winter-spring excess of births among patients with schizophrenia is not caused by any genetic or environmental risk factor that operates independently of other risk factors.
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Affiliation(s)
- Jaana M Suvisaari
- Department of Mental Health and Alcohol Research, National Public Health Institute, Mannerheimintie 166, FIN-00300 Helsinki, Finland.
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19
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Faraone SV, Brown CH, Glatt SJ, Tsuang MT. Preventing schizophrenia and psychotic behaviour: definitions and methodological issues. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2002; 47:527-37. [PMID: 12211880 DOI: 10.1177/070674370204700604] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although schizophrenia onset usually occurs in late adolescence or early adulthood, much research shows that its seeds are planted early in life and that eventual onset occurs at the end of a neurodevelopmental process leading to aberrant brain functioning. This idea, along with the fact that current therapies are far from fully effective, suggests that preventive treatments may be needed to achieve an ideal outcome for schizophrenia patients and those predisposed to the disorder. In this article, we review the methodological challenges that must be overcome before effective preventive interventions can be created. Prevention studies will need to define the target population. This requires the identification of risk factors that will be useful in selecting at-risk people for preventive treatment. We review currently identified risk factors for schizophrenia: genes, psychosocial factors, pregnancy and delivery complications, and viruses. We also review 3 different types of prevention programs: universal, indicated, and selective. For schizophrenia, we distinguish prevention programs that target prodromal cases and those that target the disorder's premorbid precursors. Although those targeting prodromal cases provide a useful framework for early treatment of the disorder, studies of premorbid individuals are needed to design a truly preventive treatment.
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Affiliation(s)
- Stephen V Faraone
- Department of Psychiatry, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA
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20
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Chotai J, Salander Renberg E. Season of birth variations in suicide methods in relation to any history of psychiatric contacts support an independent suicidality trait. J Affect Disord 2002; 69:69-81. [PMID: 12103454 DOI: 10.1016/s0165-0327(00)00379-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Due to reports on season of birth variations in suicidal behaviour as well as in cerebrospinal fluid levels of monoamine metabolites, we investigated season of birth variations in suicide methods for completed suicides in relation to any history of psychiatric contacts. Relationships with the psychiatric diagnoses for those with psychiatric contacts were also studied. METHODS Sociodemographic variables and suicide methods were examined for all the 693 suicide victims during 1961-1980 in Västerbotten, Sweden. Information on any history of psychiatric contacts was obtained from psychiatric in-patient and out-patient records. RESULTS Gender differences in the choice of suicide method were found in the group without any history of psychiatric contacts, but not in those with such a history. Only those without a history of psychiatric contacts showed season of birth variations for suicide methods -- those born during February to April were significantly more likely, and those born during October to January significantly less likely, to have preferred hanging rather than poisoning or petrol gases. These associations were stronger for the determined suicides, for males, and for urban residence. Suicide victims with a history of psychiatric contacts were significantly younger than those without. LIMITATIONS No psychological autopsies for those without psychiatric contacts. No information on eventual contacts with general practitioners. No measures of monoamine neurotransmitters were available. CONCLUSIONS Season of birth association for suicide methods is likely to be mediated by a suicidality trait independently of specific major psychiatric disorders. Monoamine neurotransmitters, particularly serotonin, are likely to underlie such a trait.
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Affiliation(s)
- Jayanti Chotai
- Division of Psychiatry, Department of Clinical Sciences, University of Umeå, Umeå, Sweden.
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21
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Abstract
The aim of this study was to ascertain whether the symptom profile distinguishes between schizophrenic patients born in the winter and early spring and those born in other seasons. The sample consisted of 204 patients with a DSM-III-R diagnosis of schizophrenia who had been hospitalized for acute psychotic decompensation. Symptom ratings were based on the Positive and Negative Syndrome Scale (PANSS). The use of demographic and anamnestic data as dependent variables did not detect any season-of-birth effect. In contrast, clear gender-specific differences emerged from the comparison focusing on symptom dimensions and clinical subtype. Female patients born in the winter and early spring had higher scores on the PANSS negative scale and anergia factor whereas male patients born in other seasons had higher scores on the PANSS anergia factor. In addition, we found a gender-specific association between season of birth and clinical subtype. Most paranoid female patients were born in the non-winter months whereas, among men, a slightly higher percentage of paranoid patients were born in winter months. These results suggest that gender plays a role in modulating the effect of the season of birth on symptoms of schizophrenia.
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Affiliation(s)
- A Troisi
- Department of Psychiatry, University of Rome Tor Vergata, Rome, Italy.
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23
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Imamura Y, Nakane Y, Ohta Y, Kondo H. Lifetime prevalence of schizophrenia among individuals prenatally exposed to atomic bomb radiation in Nagasaki City. Acta Psychiatr Scand 1999; 100:344-9. [PMID: 10563451 DOI: 10.1111/j.1600-0447.1999.tb10877.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The aim of this study was to examine the relationship between prenatal exposure to atomic bomb (A-bomb) radiation and the development of schizophrenia in adulthood. METHOD We investigated the lifetime prevalence of schizophrenia among people prenatally exposed to the 1945 Nagasaki A-bomb, using the schizophrenia register and the A-bomb survivors' database. RESULTS Among 1867 prenatally exposed individuals, 18 subjects (0.96%) had developed schizophrenia later in life. The prevalence was significantly higher in people exposed in the second trimester of pregnancy than in those exposed in the third trimester. The closer they had been to the hypocentre, the higher was the prevalence, but no statistically significant linear relationship was seen. CONCLUSION This investigation could not clarify the nature of exposure to A-bomb radiation as a risk factor for schizophrenia in the prenatal period.
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Affiliation(s)
- Y Imamura
- Department of Neuropsychiatry, Nagasaki University, School of Medicine, Japan
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24
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Blouin JL, Dombroski BA, Nath SK, Lasseter VK, Wolyniec PS, Nestadt G, Thornquist M, Ullrich G, McGrath J, Kasch L, Lamacz M, Thomas MG, Gehrig C, Radhakrishna U, Snyder SE, Balk KG, Neufeld K, Swartz KL, DeMarchi N, Papadimitriou GN, Dikeos DG, Stefanis CN, Chakravarti A, Childs B, Housman DE, Kazazian HH, Antonarakis S, Pulver AE. Schizophrenia susceptibility loci on chromosomes 13q32 and 8p21. Nat Genet 1998; 20:70-3. [PMID: 9731535 DOI: 10.1038/1734] [Citation(s) in RCA: 413] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Schizophrenia is a common disorder characterized by psychotic symptoms; diagnostic criteria have been established. Family, twin and adoption studies suggest that both genetic and environmental factors influence susceptibility (heritability is approximately 71%; ref. 2), however, little is known about the aetiology of schizophrenia. Clinical and family studies suggest aetiological heterogeneity. Previously, we reported that regions on chromosomes 22, 3 and 8 may be associated with susceptibility to schizophrenia, and collaborations provided some support for regions on chromosomes 8 and 22 (refs 9-13). We present here a genome-wide scan for schizophrenia susceptibility loci (SSL) using 452 microsatellite markers on 54 multiplex pedigrees. Non-parametric linkage (NPL) analysis provided significant evidence for an SSL on chromosome 13q32 (NPL score=4.18; P=0.00002), and suggestive evidence for another SSL on chromosome 8p21-22 (NPL=3.64; P=0.0001). Parametric linkage analysis provided additional support for these SSL. Linkage evidence at chromosome 8 is weaker than that at chromosome 13, so it is more probable that chromosome 8 may be a false positive linkage. Additional putative SSL were noted on chromosomes 14q13 (NPL=2.57; P=0.005), 7q11 (NPL=2.50, P=0.007) and 22q11 (NPL=2.42, P=0.009). Verification of suggestive SSL on chromosomes 13q and 8p was attempted in a follow-up sample of 51 multiplex pedigrees. This analysis confirmed the SSL in 13q14-q33 (NPL=2.36, P=0.007) and supported the SSL in 8p22-p21 (NPL=1.95, P=0.023).
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Affiliation(s)
- J L Blouin
- Division of Medical Genetics, University of Geneva Medical School and Cantonal Hospital, Switzerland
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25
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Abstract
Schizophrenia is generally thought to arise as a result of interactions between genetic vulnerability and environmental risk factors. However, research methods to actually investigate the pattern of hypothesized interactions have only recently been developed. In this article, we review the evidence that genes increase the risk for schizophrenia by making individuals more sensitive to environmental risk factors (genotype-environment interaction), or by making individuals more likely to select high-risk environments (genotype-environment correlation). It is likely that at least some of the impact of genes on the occurrence of schizophrenia is mediated through (sensitivity for) environmental risk factors such as a dysfunctional early family rearing environment, cannabis, viral infections, complications of birth and pregnancy, stressful life events and unknown environmental risk factors associated with urban birth or residence and membership of certain ethnic groups. With the advent of molecular genetics, further knowledge about possible genotype-environment interactions is urgently required in order to develop and improve strategies for the prevention and early treatment of schizophrenia.
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Affiliation(s)
- J van Os
- Department of Psychiatry and Neuropsychology, European Graduate School of Neuroscience, Maastricht University, The Netherlands.
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Torrey EF, Miller J, Rawlings R, Yolken RH. Seasonality of births in schizophrenia and bipolar disorder: a review of the literature. Schizophr Res 1997; 28:1-38. [PMID: 9428062 DOI: 10.1016/s0920-9964(97)00092-3] [Citation(s) in RCA: 400] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
More than 250 studies, covering 29 Northern and five Southern Hemisphere countries, have been published on the birth seasonality of individuals who develop schizophrenia and/or bipolar disorder. Despite methodological problems, the studies are remarkably consistent in showing a 5-8% winter-spring excess of births for both schizophrenia and mania/bipolar disorder. This seasonal birth excess is also found in schizoaffective disorder (December-March), major depression (March-May), and autism (March) but not in other psychiatric conditions with the possible exceptions of eating disorders and antisocial personality disorder. The seasonal birth pattern also may shift over time. Attempts to correlate the seasonal birth excess with specific features of schizophrenia suggest that winter-spring births are probably related to urban births and to a negative family history. Possible correlations include lesser severity of illness and neurophysiological measures. There appears to be no correlation with gender, social class, race, measurable pregnancy and birth complications, clinical subtypes, or neurological, neuropsychological, or neuroimaging measures. Virtually no correlation studies have been done for bipolar disorder. Regarding the cause of the birth seasonality, statistical artifact and parental procreational habits are unlikely explanations. Seasonal effects of genes, subtle pregnancy and birth complications, light and internal chemistry, toxins, nutrition, temperature/weather, and infectious agents or a combination of these are all viable possibilities.
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Affiliation(s)
- E F Torrey
- Stanley Foundation Research Programs, NIMH Neuroscience Center, St. Elizabeths Hospital, Washington, DC 20032, USA
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Dassa D, Sham PC, van Os J, Abel K, Jones P, Murray RM. Relationship of birth season to clinical features, family history, and obstetric complication in schizophrenia. Psychiatry Res 1996; 64:11-7. [PMID: 8888360 DOI: 10.1016/0165-1781(96)02868-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Birth in late winter and spring has been consistently shown to be a risk factor of schizophrenia. The relationship of late winter/spring birth to clinical characteristics and other putative risk factors, such as family history and obstetric complications, may provide clues to etiology. Data relating to season of birth, clinical features, family history, and obstetric complications were analyzed for 192 patients with schizophrenia as defined by Research Diagnostic Criteria (including schizoaffective disorder). There was no significant association of season of birth with any of the psychopathological dimensions nor was there a significant association with obstetric variables or family history. However, winter-born schizophrenic patients who had a negative family history were more likely to have a history of obstetric complications. These findings suggest that obstetric complications associated with schizophrenia are perhaps the result of some seasonal risk factors important in those without a family history of the disorder.
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Affiliation(s)
- D Dassa
- Département de Psychiatrie, C.H.U. Timone, Marseille, France
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Chen WJ, Yeh LL, Chang CJ, Lin LC, Rin H, Hwu HG. Month of birth and schizophrenia in Taiwan: effect of gender, family history and age at onset. Schizophr Res 1996; 20:133-43. [PMID: 8794501 DOI: 10.1016/0920-9964(95)00072-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Schizophrenic patients have been shown to have a moderate excess of winter births in the areas where seasonal variations in weather are large. In this report, we examined the seasonality of schizophrenic births in Taiwan, which has a subtropical climate. Using nationwide hospitalization data (2429 male and 1320 female schizophrenic patients), we applied the life table method to compare the risk of schizophrenia among 12 cohorts of month-of-birth for males and females, respectively. Differences among the risks of the 12 cohorts were tested using the logrank test. The samples were further stratified by family history and age at onset. There was a significant association between the risk of being admitted as a schizophrenic and month of birth for both males and females. The cohorts born in November and January had the highest risks. After stratification, the association was significant only for non-familial, male, and early onset schizophrenic patients. The results indicate that seasonally varying factors might increase the risk of schizophrenia, especially in those without a family history of the disease. Men are more vulnerable to such factors than women, and the schizophrenics resulting from such insults tend to be early onset.
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Affiliation(s)
- W J Chen
- Institute of Epidemiology, College of Public Health, National Taiwan University
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29
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Hettema JM, Walsh D, Kendler KS. Testing the effect of season of birth on familial risk for schizophrenia and related disorders. Br J Psychiatry 1996; 168:205-9. [PMID: 8837911 DOI: 10.1192/bjp.168.2.205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND An excess of late winter and early spring births in schizophrenia has been repeatedly demonstrated. Previous evidence has suggested that the risk for schizophrenia may differ in relatives of schizophrenic probands born in this high risk period v. at other times of the year. METHOD In an epidemiologically based family study conducted in the west of Ireland, we examined the relationship between season of birth in schizophrenia and schizophrenia spectrum probands and the risk for schizophrenia and related disorders in first-degree relatives. Risk was assessed using the Cox proportional hazard method. We examined four birth seasons previously shown to significantly predict risk for schizophrenia. RESULTS Neither the risk for schizophrenia nor that for schizophrenia spectrum disorders in relatives was significantly associated with season of birth in probands. CONCLUSIONS Season of birth does not, in this sample, identify schizophrenic probands with particularly high or low familial vulnerability to illness.
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Affiliation(s)
- J M Hettema
- Department of Psychiatry, Medical College of Virginia/VCU, Richmond 23298-0710, USA
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30
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Brown AS, Susser ES, Butler PD, Richardson Andrews R, Kaufmann CA, Gorman JM. Neurobiological plausibility of prenatal nutritional deprivation as a risk factor for schizophrenia. J Nerv Ment Dis 1996; 184:71-85. [PMID: 8596115 DOI: 10.1097/00005053-199602000-00003] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Emerging evidence indicates that schizophrenia may in some cases be a neurodevelopmental disorder, resulting in part from the effects of prenatal exposures. Studies by our group have focused attention on the potential role of prenatal nutritional deficiency as a potential etiological factor. Therefore, we sought to examine the biological plausibility of prenatal nutritional deprivation in the etiopathogenesis of schizophrenia. We conducted a review of the pertinent literature. Four lines of evidence support prenatal nutritional deficiencies as a plausible set of risk factors for schizophrenia: a) their effects are not incompatible with the epidemiology of schizophrenia; b) they have adverse effects on brain development; c) general malnutrition results in neuropathological anomalies of brain regions implicated in schizophrenia; and d) prenatal malnutrition affects maternal systems critical to the developing fetal nervous system. There is sufficient evidence to warrant further studies of prenatal nutritional deficits as risk factors for schizophrenia. A strategy for testing these hypotheses is outlined.
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Affiliation(s)
- A S Brown
- Department of Psychiatry, Columbia University, New York, 10032, USA
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Dávila R, Zumárraga M, González-Torres MA, Andía I, Zamalloa MI, Basterreche E, Guimón J, Friedhoff AJ. Schizophrenia: gender, family risk, and plasma homovanillic acid. AMERICAN JOURNAL OF MEDICAL GENETICS 1995; 60:154-6. [PMID: 7485251 DOI: 10.1002/ajmg.1320600213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Plasma homovanillic acid concentration was assessed in 60 young schizophrenic patients, with and without first-degree relatives with schizophrenia, before treatment, and 3 days after starting haloperidol treatment. The baseline concentration of homovanillic acid in plasma was no different in the two groups before treatment; it was, however, significantly higher in the patients with relatives than in those without relatives diagnosed of schizophrenia after 3 days of haloperidol treatment.
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Affiliation(s)
- R Dávila
- Departmento de Investigación Neuroquímica, Servicio Vasco de Salud, Vizcaya, Spain
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O'Callaghan E, Cotter D, Colgan K, Larkin C, Walsh D, Waddington JL. Confinement of winter birth excess in schizophrenia to the urban-born and its gender specificity. Br J Psychiatry 1995; 166:51-4. [PMID: 7894876 DOI: 10.1192/bjp.166.1.51] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND The season of birth phenomenon in schizophrenia was reexamined in relation to place of birth, in order to test the hypothesis that a seasonal factor might operate preferentially among those who were urban-born. METHOD The seasonal distribution of births was examined among 3253 patients in two case registers having an ICD-9 diagnosis of schizophrenia and compared with the distribution of births among the normal population born in those catchment areas over the same period; those subjects born in population centres greater than 50,000 were defined as urban-born. RESULTS Patients who were urban-born showed an excess of winter births relative to controls that was absent among their rural-born counterparts. On comparing patient groups, those who were urban-born were more likely to be born in the winter, while those who were rural-born were more likely to be born in the spring; this urban-rural distinction was confined essentially to female patients. CONCLUSIONS These findings might be accommodated most readily in terms of a spatially as well as seasonally varying environmental factor that is associated with urbanicity and to which female offspring are more vulnerable.
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Affiliation(s)
- E O'Callaghan
- St John of God Psychiatric Services, Cluain Mhuire Family Centre, Dublin, Ireland
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Kinney DK, Levy DL, Yurgelun-Todd DA, Medoff D, LaJonchere CM, Radford-Paregol M. Season of birth and obstetrical complications in schizophrenics. J Psychiatr Res 1994; 28:499-509. [PMID: 7699609 DOI: 10.1016/0022-3956(94)90040-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Many studies indicate that both obstetrical complications (OCs) and birth in winter or early spring are risk factors for schizophrenia, but few studies have examined how these risk factors covary in the same subjects. We assessed pre- and perinatal OCs, while blind to diagnosis, using medical data recorded at the time of subjects' births, in 29 probands with DSM-III schizophrenia or schizoaffective disorder and 39 of their unaffected adult sibs. Pre- and perinatal OCs were both significantly more common in probands than sibs. Schizophrenics not born during the winter or early spring had significantly more total and perinatal OCs than schizophrenics born in other months, but did not differ for prenatal OCs. Results indicate that OCs increase risk for schizophrenia, but also suggest the possibility that the impact of OCs on this risk may be affected by season of birth.
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Affiliation(s)
- D K Kinney
- Laboratories for Psychiatric Research, McLean Hospital, Belmont, Massachusetts 02178
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Pulver AE, Karayiorgou M, Wolyniec PS, Lasseter VK, Kasch L, Nestadt G, Antonarakis S, Housman D, Kazazian HH, Meyers D. Sequential strategy to identify a susceptibility gene for schizophrenia: report of potential linkage on chromosome 22q12-q13.1: Part 1. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 54:36-43. [PMID: 8178837 DOI: 10.1002/ajmg.1320540108] [Citation(s) in RCA: 281] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To identify genes responsible for the susceptibility for schizophrenia, and to test the hypothesis that schizophrenia is etiologically heterogeneous, we have studied 39 multiplex families from a systematic sample of schizophrenic patients. Using a complex autosomal dominant model, which considers only those with a diagnosis of schizophrenia or schizoaffective disorder as affected, a random search of the genome for detection of linkage was undertaken. Pairwise linkage analyses suggest a potential linkage (LRH = 34.7 or maximum lod score = 1.54) for one region (22q12-q13.1). Reanalyses, varying parameters in the dominant model, maximized the LRH at 660.7 (maximum lod score 2.82). This finding is of sufficient interest to warrant further investigation through collaborative studies.
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Affiliation(s)
- A E Pulver
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore 21231
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Muntaner C, Wolyniec P, McGrath J, Pulver AE. Psychotic inpatients' social class and their first admission to state or private psychiatric Baltimore hospitals. Am J Public Health 1994; 84:287-9. [PMID: 8296956 PMCID: PMC1614988 DOI: 10.2105/ajph.84.2.287] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Social class differences were investigated among patients admitted to public and private psychiatric hospitals. Participants included first admission White psychotic men admitted to Baltimore metropolitan area hospitals between 1983 and 1989. After adjusting for age and diagnosis, patients with low levels of skills/credentials were found to be more likely than patients with higher levels to be admitted to state psychiatric hospitals. These findings underscore the persistence of social class as a determinant of differences in the use of psychiatric care.
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Affiliation(s)
- C Muntaner
- National Institute of Mental Health, Bethesda, Md. 20892
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Abstract
Latent class analysis on an epidemiologically based series of 447 first contact patients with a broad diagnosis of schizophrenia revealed evidence for two subtypes: a 'neurodevelopmental' type characterized by early onset, poor pre-morbid social adjustment, restricted affect and a male:female ratio of 7:3; and a 'paranoid' type characterized by later onset, persecutory delusions and an almost equal sex ratio. A third 'schizoaffective' subtype, whose existence was less clear cut, was almost entirely confined to females and characterized by dysphoria and persecutory delusions, and had negligible familial risk of schizophrenia. The aetiological, biological and clinical significance of this typology remains to be tested.
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Affiliation(s)
- D J Castle
- Genetics Section, Institute of Psychiatry, London
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Melton B, Liang KY, Pulver AE. Extended latent class approach to the study of familial/sporadic forms of a disease: its application to the study of the heterogeneity of schizophrenia. Genet Epidemiol 1994; 11:311-27. [PMID: 7813894 DOI: 10.1002/gepi.1370110402] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
When no method exists for detecting genetic forms of a disorder, epidemiologists classify probands according to the presence or absence of an affected relative (familial or sporadic). Not only is this a surrogate measure but if the risk for the disorder is associated with characteristics such as age and gender, then probands with varied distributions of these characteristics among their relatives are subject to misclassification. A latent class approach is presented which explicitly models the relationship between the affected status of the relatives and the unobservable familial/sporadic status of the proband in order to adjust for these characteristics. Lastly, an approach is introduced to correct for attenuation in measures of association between familial/sporadic status and other variables that could result if probands are misclassified. This approach incorporates the latent class probabilities directly into the regression model without classifying probands. These methods are applied to a study of the heterogeneity of schizophrenia.
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Affiliation(s)
- B Melton
- Department of Biostatistics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205
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Ross CA, McInnis MG, Margolis RL, Li SH. Genes with triplet repeats: candidate mediators of neuropsychiatric disorders. Trends Neurosci 1993; 16:254-60. [PMID: 7689767 DOI: 10.1016/0166-2236(93)90175-l] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Recently a new form of human mutation-expansion of trinucleotide repeats-has been found to cause the diseases of fragile X syndrome, spinal and bulbar muscular atrophy, myotonic dystrophy and, most recently, Huntington's disease. We review the emerging data on the genetics and neurobiology of these disorders. Three are characterized by unusual patterns of inheritance, in particular, genetic 'anticipation', in which the severity of the disorder increases and the age of onset decreases in successive generations of a pedigree. Several idiopathic neuropsychiatric disorders have features of inheritance consistent with anticipation. In bipolar affective disorder, there is evidence for both earlier age of onset and more severe illness in the second generation of a subset of unilineal pedigrees. There is also the suggestion of anticipation in some forms of schizophrenia, spinocerebellar atrophy and autism. Triplet repeats are present in additional known genes, both in coding regions and untranslated regions. Furthermore, many novel genes with triplet repeats are expressed in the human brain, and these are candidates to cause some forms of these neuropsychiatric disorders.
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Affiliation(s)
- C A Ross
- Dept of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196
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Abstract
Recent neuroimaging and neuropathological studies suggest a developmental origin for schizophrenia. Some cases may, therefore, be caused by a genetic defect in the specification of brain development. Early environmental hazards such as obstetric complications, and maternal exposure during pregnancy to influenza epidemics, have also been found to increase the risk of later schizophrenia. The relationship between the prevalence of influenza and birth date has been found more consistently for female than male schizophrenics. Female schizophrenia is also associated with a higher risk of schizophrenia in first degree relatives. This raises the question of whether part of the genetic predisposition to schizophrenia may comprise an abnormal reaction to maternal influenza.
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Affiliation(s)
- R M Murray
- Department of Psychological Medicine, Institute of Psychiatry, London, U.K
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Abstract
The morbid risks for schizophrenia and any nonaffective psychosis in the first degree relatives of male and female schizophrenic probands were compared utilizing Cox proportional hazards models. The schizophrenic probands (275 male; 106 female) were drawn from a larger sample of hospitalized patients obtained by systematically screening all psychiatric admissions to 15 facilities over a six-year period. Proband diagnoses (DSM-III) were based on a direct assessment of the patient and a review of medical records. The family history method was used to obtain information about the first degree relatives of the probands. Cox proportional hazards models were adjusted for duration of illness of the proband and gender of the relatives. First degree relatives of female probands had significantly higher morbid risks for schizophrenia and nonaffective psychosis than relatives of male probands. The differential risk for schizophrenia in the relatives of male and female probands demonstrated in this study, as well as others, suggests that males and females may be at different risk for subtypes of the disorder.
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Affiliation(s)
- P S Wolyniec
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21203
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