Association analysis of Neuregulin 1 candidate regions in schizophrenia and bipolar disorder.
ABSTRACT Schizophrenia (SCZ) and bipolar disorder (BPD) are severe heritable psychiatric disorders involving a complex genetic aetiology. Neuregulin 1 (NRG1) is a leading candidate gene for SCZ, and has recently been implicated in BPD. We previously reported association of two NRG1 haplotypes with SCZ and BPD in a Scottish case-control sample. One haplotype is located at the 5' end of the gene (region A), and the other is located at the 3' end (region B). Here, association to haplotypes within regions A and B was assessed in patients with SCZ and BPD in a second Scottish case-control sample and in the two Scottish samples combined. Association to region B was also assessed in patients with SCZ and BPD in a German case-control sample, and in all three samples combined. No evidence was found for association in the new samples when analysed individually; however, in the joint analysis of the two Scottish samples, a region B haplotype comprising two SNPs (rs6988339 and rs3757930) was associated with SCZ and the combined case group (SCZ: p=0.0037, OR=1.3, 95% CI: 1.1-1.6; BPD+SCZ: p=0.0080, OR=1.2, 95% CI: 1.1-1.5), with these associations withstanding multiple testing correction at the single-test level (SCZ: p(st)=0.022; BPD+SCZ: p(st)=0.044). This study supports the involvement of NRG1 variants in the less well studied 3' region in conferring susceptibility to SCZ and BPD in the Scottish population.
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ABSTRACT: Patients with schizophrenia are at an increased risk for the development of depression. Overlap in the symptoms and genetic risk factors between the two disorders suggests a common etiological mechanism may underlie the presentation of comorbid depression in schizophrenia. Understanding these shared mechanisms will be important in informing the development of new treatments. Rodent models are powerful tools for understanding gene function as it relates to behavior. Examining rodent models relevant to both schizophrenia and depression reveals a number of common mechanisms. Current models which demonstrate endophenotypes of both schizophrenia and depression are reviewed here, including models of CUB and SUSHI multiple domains 1, PDZ and LIM domain 5, glutamate Delta 1 receptor, diabetic db/db mice, neuropeptide Y, disrupted in schizophrenia 1, and its interacting partners, reelin, maternal immune activation, and social isolation. Neurotransmission, brain connectivity, the immune system, the environment, and metabolism emerge as potential common mechanisms linking these models and potentially explaining comorbid depression in schizophrenia.Frontiers in Psychiatry 02/2015; 6:13. DOI:10.3389/fpsyt.2015.00013
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ABSTRACT: Synaptic plasticity alters the strength of information flow between presynaptic and postsynaptic neurons and thus modifies the likelihood that action potentials in a presynaptic neuron will lead to an action potential in a postsynaptic neuron. As such, synaptic plasticity and pathological changes in synaptic plasticity impact the synaptic computation which controls the information flow through the neural microcircuits responsible for the complex information processing necessary to drive adaptive behaviors. As current theories of neuropsychiatric disease suggest that distinct dysfunctions in neural circuit performance may critically underlie the unique symptoms of these diseases, pathological alterations in synaptic plasticity mechanisms may be fundamental to the disease process. Here we consider mechanisms of both short-term and long-term plasticity of synaptic transmission and their possible roles in information processing by neural microcircuits in both health and disease. As paradigms of neuropsychiatric diseases with strongly implicated risk genes, we discuss the findings in schizophrenia and autism and consider the alterations in synaptic plasticity and network function observed in both human studies and genetic mouse models of these diseases. Together these studies have begun to point toward a likely dominant role of short-term synaptic plasticity alterations in schizophrenia while dysfunction in autism spectrum disorders (ASDs) may be due to a combination of both short-term and long-term synaptic plasticity alterations.Frontiers in Synaptic Neuroscience 11/2014; 6:28. DOI:10.3389/fnsyn.2014.00028
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ABSTRACT: schizophrenia is a complex mental disorder marked by severely impaired thinking, delusional thoughts, hallucinations and poor emotional responsiveness. The biological mechanisms that lead to schizophrenia may be related to the genetic background of patients. Thus, a genetic perspective may help to unravel the molecular pathways disrupted in schizophrenia. In the present work, we used a molecular pathway analysis to identify the molecular pathways associated with schizophrenia. We collected data of genetic loci previously associated with schizophrenia, identified the genes located in those positions and created the metabolic pathways that are related to those genes' products. These pathways were tested for enrichment (a number of SNPs associated with the phenotype significantly higher than expected by chance) in a sample of schizophrenic patients and controls (4,486 and 4,477, respectively). The molecular pathway that resulted from the identification of all the genes located in loci previously found to be associated with schizophrenia was found to enriched, as expected (permutated p(10(6))=9.9999e-06).We found 60 SNPs amongst 30 different genes with a strong association with schizophrenia. The genes are related to the pathways related to neurodevelopment, apoptosis, vesicle traffic, immune response and MAPk cascade. The pathway related to the toll-like receptor family seemed to play a central role in the modulation/connection of various pathways whose disruption leads to schizophrenia. This pathway is related to the innate immune system, further stressing the role of immunological-related events in increasing the risk to schizophrenia. Copyright © 2014. Published by Elsevier Inc.Progress in Neuro-Psychopharmacology and Biological Psychiatry 12/2014; 59. DOI:10.1016/j.pnpbp.2014.12.009 · 4.03 Impact Factor