Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unstable trinucleotide repeat DNA contained in numerous genes has been proposed as the underlying mechanism in the clinical phenomenon of genetic anticipation in fragile X syndrome and other neurodegenerative diseases. No clear evidence has been found for the role of these abnormal trinucleotide repeat expansion-containing genes in schizophrenia or other psychiatric disorders. This report describes an adult male with psychosis who was later found to have methylation mosaicism of the FMR1 gene. We discuss history, examination, and investigation which led to the diagnosis and treatment response of this patient.
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PMID:Clinical description of an adult male with psychosis who showed FMR1 gene methylation mosaicism. 960 8

Unstable (CAG)n trinucleotide repeat microsatellites are hypothesized to cause schizophrenia. The (CAG)n microsatellite of dominant spinal cerebellar ataxia type 1 (SCA1) is a candidate schizophrenia gene. Autism results from expansions of (CGG)n and (GAA)n trinucleotide repeat stretches at fragile X syndrome (FRAXA), and the recessive Friedreich's ataxia (FA). Dominant ataxia genes may cause schizophrenia and recessive ataxia genes may cause autism. Syndromes with autism show purine synthesis defects (PSDs) and/or pigmentation defects (PDs). Autism is caused by very lengthy expansions of (CAG)n, (CGG)n and (GAA)n repeats, while schizophrenia results from much smaller (CAG)n and (CGG)n repeat expansions.
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PMID:Expanded (CAG)n, (CGG)n and (GAA)n trinucleotide repeat microsatellites, and mutant purine synthesis and pigmentation genes cause schizophrenia and autism. 979

Trinucleotide, or triplet, repeats consist of 3 nucleotides consecutively repeated (e.g., CCG CCG CCG CCG CCG) within a region of DNA, a not uncommon motif in the genome of humans and other species. In 1991, a new type of genetic mutation was discovered, known as a dynamic or expansion mutation, in which the number of triplets in a repeat increases and the length becomes unstable. During the past decade, nearly 20 diseases-including Huntington disease, 2 forms of the fragile X syndrome, and myotonic dystrophy-caused by trinucleotide repeat expansions have been identified. The unstable nature of the expanded repeat leads to remarkable patterns of inheritance in these diseases, distinctly at odds with traditional notions of mendelian genetics. We review the clinical and genetic features of these disorders, with a particular emphasis on their psychiatric manifestations. We also critically examine the hypothesis that expansion mutations may have an etiologic role in psychiatric diseases such as bipolar disorder, schizophrenia, and autism.
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PMID:Trinucleotide repeat expansion and neuropsychiatric disease. 1056 2

CX-516 is one of a series of AMPA modulators under development by Cortex, in collaboration with Shire and Servier, for the potential treatment of Alzheimer's disease (AD), schizophrenia and mild cognitive impairment (MCI) [234221]. By June 2001, CX-516 was in phase II trials for both schizophrenia and attention deficit hyperactivity disorder (ADHD) [412513]. A phase II trial in fragile X syndrome and autism was expected to start in May 2002 [449861]. In October 2001, Cortex was awarded a Phase II SBIR grant of $769,818 from the National Institutes of Mental Health to investigate the therapeutic potential of AMPAkines in schizophrenia. This award was to support a phase IIb study of CX-516 as a combination therapy in schizophrenia patients concomitantly treated with olanzapine. The trial was to enroll 80 patients and employ a randomized, double-blind, placebo-controlled design in which the placebo group was to receive olanzapine plus placebo and the active group was to receive olanzapine plus CX-516 [425982]. In April 2000, Shire and Cortex signed an option agreement in which Shire was to evaluate CX-516for the treatment of ADHD. Under the terms of the agreement, Shire would undertake a double-blind, placebo-controlled evaluation of CX-516 involving ADHD patients. If the study proved effective, Shire would have the right to convert its option into an exclusive worldwide license for the AMPAkines for ADHD under a development and licensing agreement. Should Shire elect to execute this agreement, Shire would bear all future developmental costs [363618]. By February 2002, Cortex and Servier had revealed their intention to begin enrolment for an international study of an AMPAkine compound as a potential treatment for MCI in the near future. Assuming enrollment proceeded as anticipated, results were expected during the second quarter of 2003 [439301]. By May 2002, phase II trials were underway [450134]. In March 2002, Cortex was awarded extended funding under the University of California BioSTAR projectfor the research project: 'Ampakine modulation of brain neurotrophin expression: a novel therapeutic strategy'. This funding was expected to amount to $193,000 over a two-year period [444872].
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PMID:CX-516 Cortex pharmaceuticals. 1218 71

Researchers and clinicians are increasingly recognizing that psychological and psychiatric disorders are often developmentally progressive, and that diagnosis often represents a point along that progression that is defined largely by our abilities to detect symptoms. As a result, strategies that guide our searches for the root causes and etiologies of these disorders are beginning to change. This review describes interactions between genetics and experience that influence the development of psychopathologies. Following a discussion of normal brain development that highlights how specific cellular processes may be targeted by genetic or environmental factors, we focus on four disorders whose origins range from genetic (fragile X syndrome) to environmental (fetal alcohol syndrome) or a mixture of both factors (depression and schizophrenia). C.H. Waddington's canalization model (slightly modified) is used as a tool to conceptualize the interactive influences of genetics and experience in the development of these psychopathologies. Although this model was originally proposed to describe the 'canalizing' role of genetics in promoting normative development, it serves here to help visualize, for example, the effects of adverse (stressful) experience in the kindling model of depression, and the multiple etiologies that may underlie the development of schizophrenia. Waddington's model is also useful in understanding the canalizing influence of experience-based therapeutic approaches, which also likely bring about 'organic' changes in the brain. Finally, in light of increased evidence for the role of experience in the development and treatment of psychopathologies, we suggest that future strategies for identifying the underlying causes of these disorders be based less on the mechanisms of action of effective pharmacological treatments, and more on increased knowledge of the brain's cellular mechanisms of plastic change.
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PMID:Experience effects on brain development: possible contributions to psychopathology. 1255 12

Dynamic mutations in human genes result from unstable trinucleotide repeats which are expanded within the genome. These expansions of trinucleotide repeats have been shown to be the etiological factors in various neuropsychiatric diseases and other genetic disorders. This hypothesis is supported by various independent studies showing large expansion of trimeric repeats, such as CAG/CTG/CCG/CGG/AAG, in patient DNA samples. These repeats are also identified in other disease loci not clearly related to particular diseases, which indicates that such expansions are one of the general forms of evolution occurring throughout the human genome. The trinucleotide repeat expansions occur during meiosis and are generally irreversible. Accumulation of these repeats over generations eventually ends in a deficiency of replication. There is evidence that certain ethnic groups in the human population have predispositions for expanded repeats related to neuropsychiatric diseases. It is likely that racial/ethnic differences reflect variations, which suggests the possibility of an underlying complex biological process. The present review highlights the importance of repeat expansions in some neuropsychiatric diseases, such as spinal and bulbular atrophy (SBMA), spinocerebellar ataxia (SCA), Huntington's disease (HD), schizophrenia, myotonic dystrophy (DM) and fragile-X syndrome.
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PMID:DNA trinucleotide repeat expansion in neuropsychiatric patients. 1296 Sep 39

Magnetic resonance imaging (MRI) has opened a new window to the brain. Measuring hippocampal volume with MRI has provided important information about several neuropsychiatric disorders. We reviewed the literature and selected all English-language, human subject, data-driven papers on hippocampal volumetry, yielding a database of 423 records. Smaller hippocampal volumes have been reported in epilepsy, Alzheimer's disease, dementia, mild cognitive impairment, the aged, traumatic brain injury, cardiac arrest, Parkinson's disease, Huntington's disease, Cushing's disease, herpes simplex encephalitis, Turner's syndrome, Down's syndrome, survivors of low birth weight, schizophrenia, major depression, posttraumatic stress disorder, chronic alcoholism, borderline personality disorder, obsessive-compulsive disorder, and antisocial personality disorder. Significantly larger hippocampal volumes have been correlated with autism and children with fragile X syndrome. Preservation of hippocampal volume has been reported in congenital hyperplasia, children with fetal alcohol syndrome, anorexia nervosa, attention-deficit and hyperactivity disorder, bipolar disorder, and panic disorder. Possible mechanisms of hippocampal volume loss in neuropsychiatric disorders are discussed.
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PMID:MR-based in vivo hippocampal volumetrics: 2. Findings in neuropsychiatric disorders. 1535 39

Genotype-phenotype relationship studies for psychiatric disorders in females carrying fragile X syndrome full mutation and premutation underline association with schizo-affective disorders. In female children with X fragile full mutation, only behavioural symptoms and no standardised psychiatric disorders have been systematically explored. Therefore, we report the case of a nine-year-old girl carrying the fragile X syndrome full mutation with a comorbid childhood onset schizophrenia (COS), and of her mother carrying the fragile X syndrome premutation and a comorbid schizotypal personality disorder. The impact of these associations is discussed regarding the recent literature in chromosome anomalies in COS.
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PMID:[Fragile X syndrome and very early onset schizophrenia: a female case study]. 1569 44

Drugs that potentiate the activity of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor cause a complex cascade of consequences in experimental models, ranging from enhancement of long-term potentiation to induction of neurotrophic factors. Animal studies characterising the pharmacological and behavioural effects of these substances have provided the rationale for several initial attempts to use these drugs in neuropsychiatric clinical settings. Applications in schizophrenia, Alzheimer's disease and mild cognitive impairment have been initiated. Other trials with these compounds include the treatment of Fragile X syndrome, and possible future applications may be in the field of Parkinson's disease. The literature published to date is limited mostly to small phase I or II trials, so there is no conclusive evidence for or against the use of these drugs. Substantial questions remain concerning which compounds to use, in what dose, for what condition and for how long.
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PMID:Therapeutic potential of positive AMPA receptor modulators in the treatment of neuropsychiatric disorders. 1652 24

Allosteric modulators of metabotropic glutamate receptor subtype 5 (mGluR5) have been developed for their therapeutic potential in a variety of disorders including schizophrenia, drug abuse, fragile X syndrome and anxiety. Modulation of the receptor through an allosteric mechanism provides a high degree of selectivity and avoids many of the pitfalls that are associated with direct acting ligands, such as receptor desensitization. Drug discovery activities in this field have advanced rapidly in recent years, with the development of lead compounds often being accelerated through a variety of novel technologies. The promising effects observed for allosteric modulators of mGluR5 in preclinical studies suggest that their continued development may provide therapeutic options for a range of psychiatric and neurological disorders.
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PMID:Recent progress in the development of allosteric modulators of mGluR5. 1798 23


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