The role of the CNR1 gene in schizophrenia: a systematic review including unpublished data

Objective: Schizophrenia is a multifactorial disorder. It is known that a combination of extensive multiple common alleles may be involved in its etiology, each contributing with a small to moderate effect, and, possibly, some rare alleles with a much larger effect size. We aimed to perform a systematic review of association studies between schizophrenia (and its subphenotypes) and polymorphisms in the CNR1 gene, which encodes cannabinoid receptors classically implicated in schizophrenia pathophysiology, as well as to present unpublished results of an association study in a Brazilian population. Methods: Two reviewers independently searched for eligible studies and extracted outcome data using a structured form. Papers were retrieved from PubMed and ISI Web of Knowledge using the search term schizophrenia in combination with CNR1 or CB1 or cannabinoid receptor. Twenty-four articles met our inclusion criteria. We additionally present data from a study of our own comparing 182 patients with schizophrenia and 244 healthy controls. Results: No consistent evidence is demonstrated. Conclusion: Some seemingly positive association studies stress the need for further investigations of the possible role of endocannabinoid genetics in schizophrenia.Fundacao de Amparo e Pesquisa do Estado de Sao Paulo (FAPESP) [2010/08968-6, 2011/50740-5, 2011/00030-1]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)FAPESPCNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Fundacao SafraFundacao ABADSUniv Fed Sao Paulo UNIFESP, Dept Psiquiatria, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Lab Interdisciplinar Neurociencias Clin LiNC, Sao Paulo, SP, BrazilIrmandade Santa Casa Misericordia Sao Paulo, Dept Psiquiatria, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Morfol & Genet, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Dept Psiquiatria, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Lab Interdisciplinar Neurociencias Clin LiNC, Sao Paulo, SP, BraziWeb of Scienc

Catechol-O-methyltransferase (COMT) polymorphisms modulate working memory in individuals with schizophrenia and healthy controls

Objective: Cognitive impairment is a core feature of schizophrenia, related to dopaminergic dysfunction in the prefrontal cortex (PFC). It is hypothesized that functional single nucleotide polymorphism (SNP) rs4680 of the catechol-O-methyltransferase (COMT) gene could mediate the relationship between cognition and dopamine activity in the PFC. Other COMT SNPs could also play a role. Methods: We evaluated the role of three COMT SNPs (rs737865, rs165599, and rs4680) in schizophrenia and their impact on three working memory tasks. For genetic association analyses, 212 individuals with schizophrenia and 257 healthy controls (HCs) were selected. The Visual Working Memory (VWM) Task, Keep Track Task, and Letter Memory Task were administered to 133 schizophrenics and 93 HCs. Results: We found a significant association of rs737865, with the GG genotype exerting a protective effect and the GA haplotype (rs4680/rs165599) exerting a risk effect for schizophrenia. COMT rs4680 AA carriers and rs737865 AA carriers scored lowest on the Keep Track Task. When the genotype* group interaction effect was evaluated, rs165599 exerted opposite effects for VWM and Keep Track task performance in patients and controls, with AA carriers scoring lowest on both tests among controls, but highest among patients. Conclusion: These data support the hypothesis that COMT polymorphisms may be associated with schizophrenia and modulate cognition in patients and controls.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), BrazilUniv Fed Sao Paulo UNIFESP, Dept Psiquiatria, Sao Paulo, SP, BrazilFMABC, Dept Saude Colet, Santo Andre, SP, BrazilUniv Fed Sao Paulo, Lab Interdisciplinar Neurociencias Clin LiNC, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Morfol & Genet, Disciplina Genet, Sao Paulo, SP, BrazilCtr Univ Fundcao Inst Ensino Osasco UNIFIEO, Dept Psicol Educ, Osasco, SP, BrazilUniv Fed Sao Paulo, Dept Psicobiol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Dept Psiquiatria, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Lab Interdisciplinar Neurociencias Clin LiNC, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Morfol & Genet, Disciplina Genet, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Psicobiol, Sao Paulo, SP, BrazilFAPESP: 2007/58736-1FAPESP: 2011/50740-5Web of Scienc

PRODH Polymorphisms, Cortical Volumes and Thickness in Schizophrenia

Schizophrenia is a neurodevelopmental disorder with high heritability. Several lines of evidence indicate that the PRODH gene may be related to the disorder. Therefore, our study investigates the effects of 12 polymorphisms of PRODH on schizophrenia and its phenotypes. To further evaluate the roles of the associated variants in the disorder, we have conducted magnetic resonance imaging (MRI) scans to assess cortical volumes and thicknesses. A total of 192 patients were evaluated using the Structured Clinical Interview for DSM-IV (SCID), Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale, Global Assessment of Functioning (GAF) and Clinical Global Impression (CGI) instruments. the study included 179 controls paired by age and gender. the samples were genotyped using the real-time polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP)-PCR and Sanger sequencing methods. A sample of 138 patients and 34 healthy controls underwent MRI scans. One polymorphism was associated with schizophrenia (rs2904552), with the G-allele more frequent in patients than in controls. This polymorphism is likely functional, as predicted by PolyPhen and SIFT, but it was not associated with brain morphology in our study. in summary, we report a functional PRODH variant associated with schizophrenia that may have a neurochemical impact, altering brain function, but is not responsible for the cortical reductions found in the disorder.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo UNIFESP, Disciplina Genet, Dept Morfol & Genet, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, LiNC, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Psiquiatria, São Paulo, BrazilFac Med ABC FMABC, Dept Ginecol & Obstet, Disciplina Genet & Reprod Humana, São Paulo, BrazilFed Univ Para, Lab Genet Humana & Med, BR-66059 Belem, Para, BrazilUniv Fed ABC, Ctr Math Computat & Cognit, Santo Andre, BrazilUniversidade Federal de São Paulo UNIFESP, Disciplina Genet, Dept Morfol & Genet, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, LiNC, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Psiquiatria, São Paulo, BrazilFAPESP: 2011/50740-5FAPESP: 2007/58736-1Web of Scienc

Mapping genomic loci implicates genes and synaptic biology in schizophrenia

Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies

Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe

Breakpoint mapping in a case of mosaicism with partial monosomy 9p23 -> pter and partial trisomy 1q41 -> qter suggests neo-telomere formation in stabilizing the deleted chromosome

We report on a clinical and molecular cytogenetic study of a patient who presents a complex chromosomal rearrangement with two different cell lines. Using high-resolution GTG handing and fluorescence in situ hybridization (FISH) with several probes, including bacterial artificial chromosomes (BACs), the karyotype was defined as 46,XX,del(9)(p23)[54]/ 46,XX,der(9)t(1;9)(q41;p23)[461, indicating the presence of monosomy 9p23 in all cells and trisomy 1q41 in approximately 50% of the cells. the patient studied presents most of the manifestations of the 9p deletion and 1q duplication syndromes. the breakpoint was mapped at 9p23 with a loss of approximately 13.9-Mb of DNA. the duplicated segment consists of approximately 35 Mb from 1q41-qter region. We also suggest that a mechanism for telomere capture and interstitial telomeric sequences (ITs) is involved in a neotelomere formation in one of the cell lines. This study highlights the importance of combining high-resolution chromosome and FISH with BACs in order to make genotype -phenotype correlations and to understand the mechanisms involved chromosomal aberrations. (c) 2005 Wiley-Liss, Inc.Universidade Federal de São Paulo, Disciplina Genet, Dept Morphol, Div Genet, BR-04023900 São Paulo, BrazilCase Western Reserve Univ, Ctr Human Genet, Cleveland, OH 44106 USACase Western Reserve Univ, Dept Genet, Cleveland, OH 44106 USAUniv Hosp Cleveland, Cleveland, OH 44106 USAUniv Chicago, Dept Human Genet, Chicago, IL 60637 USAUniversidade Federal de São Paulo, Disciplina Genet, Dept Morphol, Div Genet, BR-04023900 São Paulo, BrazilWeb of Scienc