Abnormal elevation of FMR1 mRNA is associated with psychological symptoms in individuals with the fragile X premutation

Authors

  • David Hessl,

    Corresponding author
    1. Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California-Davis Medical Center, Sacramento, California
    2. Department of Psychiatry and Behavioral Sciences, University of California-Davis Medical Center, Sacramento, California
    • Assistant Clinical Professor, M.I.N.D. Institute, U.C. Davis Medical Center, 2825 50th Street, Sacramento, CA 95817.
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  • Flora Tassone,

    1. Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California-Davis Medical Center, Sacramento, California
    2. Department of Biological Chemistry, University of California-Davis School of Medicine, Davis, California
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  • Danuta Z. Loesch,

    1. School of Psychological Science, La Trobe University, Melbourne, Victoria, Australia
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  • Elizabeth Berry-Kravis,

    1. Department of Pediatrics, RUSH University Medical Center, Chicago, Illinois
    2. Department of Neurology, RUSH University Medical Center, Chicago, Illinois
    3. Department of Biochemistry, RUSH University Medical Center, Chicago, Illinois
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  • Maureen A. Leehey,

    1. Department of Neurology, University of Colorado Health Sciences Center, Denver, Colorado
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  • Louise W. Gane,

    1. Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California-Davis Medical Center, Sacramento, California
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  • Ingrid Barbato,

    1. Neurogene Clinical Laboratory, Florianopolis, Brazil
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  • Cathlin Rice,

    1. Department of Neurology, University of Colorado Health Sciences Center, Denver, Colorado
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  • Emma Gould,

    1. School of Psychological Science, La Trobe University, Melbourne, Victoria, Australia
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  • Deborah A. Hall,

    1. Department of Neurology, University of Colorado Health Sciences Center, Denver, Colorado
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  • James Grigsby,

    1. Department of Geriatrics, University of Colorado Health Sciences Center, Denver, Colorado
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  • Jacob A. Wegelin,

    1. Department of Psychiatry and Behavioral Sciences, University of California-Davis Medical Center, Sacramento, California
    2. Division of Biostatistics, University of California-Davis School of Medicine, Davis, California
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  • Susan Harris,

    1. Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California-Davis Medical Center, Sacramento, California
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  • Foster Lewin,

    1. Department of Pediatrics, RUSH University Medical Center, Chicago, Illinois
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  • Dahlia Weinberg,

    1. Department of Pediatrics, RUSH University Medical Center, Chicago, Illinois
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  • Paul J. Hagerman,

    1. Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California-Davis Medical Center, Sacramento, California
    2. Department of Biological Chemistry, University of California-Davis School of Medicine, Davis, California
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  • Randi J. Hagerman

    1. Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California-Davis Medical Center, Sacramento, California
    2. Department of Pediatrics, University of California-Davis Medical Center, Sacramento, California
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Abstract

Until recently, individuals with premutation alleles (55–200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene were believed to be psychologically unaffected. However, the recent documentation of abnormal elevation of FMR1 mRNA, discovery of fragile X-associated tremor/ataxia syndrome (FXTAS), and reports of psychiatric disorders in children and adults with the premutation have suggested a pathogenic gene–brain–behavior mechanism. In a large collaborative study, 68 men and 144 women with the FMR1 premutation completed a psychological symptoms checklist and FMR1 genetic testing, including determination of CGG repeat size, percentage of FMR1 protein (FMRP)-positive lymphocytes, and FMR1 mRNA levels. Relative to published norms, men and women with FXTAS symptoms reported higher levels of several types of psychological symptoms. In addition, men and women with the premutation and no overt evidence of FXTAS reported higher levels of obsessive-compulsive symptoms. Elevated FMR1 mRNA, but not CGG repeat size or reduced FMRP (as measured by immunocytochemistry), was significantly associated with increased psychological symptoms, predominantly obsessive-compulsive symptoms and psychoticism, in premutation men with and without FXTAS symptoms. There was no relationship between CGG repeat size, FMR1 mRNA or FMRP and psychological symptoms in premutation women unless the sample was restricted to those with skewed X-activation ratio toward >50% active premutation alleles. The results of this study support the hypothesis that FMR1 function is associated with psychological difficulties in individuals with the premutation, and provide evidence concordant with an RNA toxic gain-of-function model in a neuropsychiatric phenotype. © 2005 Wiley-Liss, Inc.

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