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Barbé L, Finkbeiner S. Genetic and Epigenetic Interplay Define Disease Onset and Severity in Repeat Diseases. Front Aging Neurosci 2022; 14:750629. [PMID: 35592702 PMCID: PMC9110800 DOI: 10.3389/fnagi.2022.750629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Repeat diseases, such as fragile X syndrome, myotonic dystrophy, Friedreich ataxia, Huntington disease, spinocerebellar ataxias, and some forms of amyotrophic lateral sclerosis, are caused by repetitive DNA sequences that are expanded in affected individuals. The age at which an individual begins to experience symptoms, and the severity of disease, are partially determined by the size of the repeat. However, the epigenetic state of the area in and around the repeat also plays an important role in determining the age of disease onset and the rate of disease progression. Many repeat diseases share a common epigenetic pattern of increased methylation at CpG islands near the repeat region. CpG islands are CG-rich sequences that are tightly regulated by methylation and are often found at gene enhancer or insulator elements in the genome. Methylation of CpG islands can inhibit binding of the transcriptional regulator CTCF, resulting in a closed chromatin state and gene down regulation. The downregulation of these genes leads to some disease-specific symptoms. Additionally, a genetic and epigenetic interplay is suggested by an effect of methylation on repeat instability, a hallmark of large repeat expansions that leads to increasing disease severity in successive generations. In this review, we will discuss the common epigenetic patterns shared across repeat diseases, how the genetics and epigenetics interact, and how this could be involved in disease manifestation. We also discuss the currently available stem cell and mouse models, which frequently do not recapitulate epigenetic patterns observed in human disease, and propose alternative strategies to study the role of epigenetics in repeat diseases.
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Affiliation(s)
- Lise Barbé
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
| | - Steve Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
- *Correspondence: Steve Finkbeiner,
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Maltman N, Guilfoyle J, Nayar K, Martin GE, Winston M, Lau JCY, Bush L, Patel S, Lee M, Sideris J, Hall DA, Zhou L, Sharp K, Berry-Kravis E, Losh M. The Phenotypic Profile Associated With the FMR1 Premutation in Women: An Investigation of Clinical-Behavioral, Social-Cognitive, and Executive Abilities. Front Psychiatry 2021; 12:718485. [PMID: 34421690 PMCID: PMC8377357 DOI: 10.3389/fpsyt.2021.718485] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/12/2021] [Indexed: 11/23/2022] Open
Abstract
The FMR1 gene in its premutation (PM) state has been linked to a range of clinical and subclinical phenotypes among FMR1 PM carriers, including some subclinical traits associated with autism spectrum disorder (ASD). This study attempted to further characterize the phenotypic profile associated with the FMR1 PM by studying a battery of assessments examining clinical-behavioral traits, social-cognitive, and executive abilities in women carrying the FMR1 PM, and associations with FMR1-related variability. Participants included 152 female FMR1 PM carriers and 75 female controls who were similar in age and IQ, and screened for neuromotor impairments or signs of fragile X-associated tremor/ataxia syndrome. The phenotypic battery included assessments of ASD-related personality and language (i.e., pragmatic) traits, symptoms of anxiety and depression, four different social-cognitive tasks that tapped the ability to read internal states and emotions based on different cues (e.g., facial expressions, biological motion, and complex social scenes), and a measure of executive function. Results revealed a complex phenotypic profile among the PM carrier group, where subtle differences were observed in pragmatic language, executive function, and social-cognitive tasks that involved evaluating basic emotions and trustworthiness. The PM carrier group also showed elevated rates of ASD-related personality traits. In contrast, PM carriers performed similarly to controls on social-cognitive tasks that involved reliance on faces and biological motion. The PM group did not differ from controls on self-reported depression or anxiety symptoms. Using latent profile analysis, we observed three distinct subgroups of PM carriers who varied considerably in their performance across tasks. Among PM carriers, CGG repeat length was a significant predictor of pragmatic language violations. Results suggest a nuanced phenotypic profile characterized by subtle differences in select clinical-behavioral, social-cognitive, and executive abilities associated with the FMR1 PM in women.
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Affiliation(s)
- Nell Maltman
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Janna Guilfoyle
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Kritika Nayar
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Gary E. Martin
- Department of Communication Sciences and Disorders, St. John's University, Staten Island, NY, United States
| | - Molly Winston
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Joseph C. Y. Lau
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Lauren Bush
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Shivani Patel
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Michelle Lee
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - John Sideris
- Chan Division of Occupational Science and Occupational Therapy, University of Southern California, Los Angeles, CA, United States
| | - Deborah A. Hall
- Department of Neurological Sciences, Rush University, Chicago, IL, United States
| | - Lili Zhou
- Rush University Medical Center, Chicago, IL, United States
| | - Kevin Sharp
- Rush University Medical Center, Chicago, IL, United States
| | | | - Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
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Storey E, Bui MQ, Stimpson P, Tassone F, Atkinson A, Loesch DZ. Relationships between motor scores and cognitive functioning in FMR1 female premutation X carriers indicate early involvement of cerebello-cerebral pathways. CEREBELLUM & ATAXIAS 2021; 8:15. [PMID: 34116720 PMCID: PMC8196444 DOI: 10.1186/s40673-021-00138-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 05/28/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Smaller expansions of CGG trinucleotide repeats in the FMR1 X-linked gene termed 'premutation' lead to a neurodegenerative disorder: Fragile X Associated Tremor/Ataxia Syndrome (FXTAS) in nearly half of aged carrier males, and 8-16% females. Core features include intention tremor, ataxia, and cognitive decline, and white matter lesions especially in cerebellar and periventricular locations. A 'toxic' role of elevated and expanded FMR1 mRNA has been linked to the pathogenesis of this disorder. The emerging issue concerns the trajectory of the neurodegenerative changes: is the pathogenetic effect confined to overt clinical manifestations? Here we explore the relationships between motor and cognitive scale scores in a sample of 57 asymptomatic adult female premutation carriers of broad age range. METHODS Three motor scale scores (ICARS-for tremor/ataxia, UPDRS-for parkinsonism, and Clinical Tremor) were related to 11 cognitive tests using Spearman's rank correlations. Robust regression, applied in relationships between all phenotypic measures, and genetic molecular and demographic data, identified age and educational levels as common correlates of these measures, which were then incorporated as confounders in correlation analysis. RESULTS Cognitive tests demonstrating significant correlations with motor scores were those assessing non-verbal reasoning on Matrix Reasoning (p-values from 0.006 to 0.011), and sequencing and alteration on Trails-B (p-values from 0.008 to 0.001). Those showing significant correlations with two motor scores-ICARS and Clinical Tremor- were psychomotor speed on Symbol Digit Modalities (p-values from 0.014 to 0.02) and working memory on Digit Span Backwards (p-values from 0.024 to 0.011). CONCLUSIONS Subtle motor impairments correlating with cognitive, particularly executive, deficits may occur in female premutation carriers not meeting diagnostic criteria for FXTAS. This pattern of cognitive deficits is consistent with those seen in other cerebellar disorders. Our results provide evidence that more than one category of clinical manifestation reflecting cerebellar changes - motor and cognitive - may be simultaneously affected by premutation carriage across a broad age range in asymptomatic carriers.
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Affiliation(s)
- Elsdon Storey
- Department of Medicine (Neuroscience), Monash University, 5th Floor, Centre Block, Alfred Hospital Campus, Commercial Road, Melbourne, Victoria, 3004, Australia.
| | - Minh Q Bui
- Centre for Molecular, Environmental, Genetic and Analytic, Epidemiology, University of Melbourne, Parkville, Victoria, Australia
| | - Paige Stimpson
- Wellness and Recovery Centre, Monash Medical Centre, Clayton, Victoria, Australia
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Davis, California, USA
| | - Anna Atkinson
- School of Psychology and Public Health, La Trobe University, Melbourne, Bundoora, Victoria, Australia
| | - Danuta Z Loesch
- School of Psychology and Public Health, La Trobe University, Melbourne, Bundoora, Victoria, Australia
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Loesch DZ, Tassone F, Atkinson A, Stimpson P, Trost N, Pountney DL, Storey E. Differential Progression of Motor Dysfunction Between Male and Female Fragile X Premutation Carriers Reveals Novel Aspects of Sex-Specific Neural Involvement. Front Mol Biosci 2021; 7:577246. [PMID: 33511153 PMCID: PMC7835843 DOI: 10.3389/fmolb.2020.577246] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022] Open
Abstract
Expansions of the CGG repeat in the non-coding segment of the FMR1 X-linked gene are associated with a variety of phenotypic changes. Large expansions (>200 repeats), which cause a severe neurodevelopmental disorder, the fragile x syndrome (FXS), are transmitted from the mothers carrying smaller, unstable expansions ranging from 55 to 200 repeats, termed the fragile X premutation. Female carriers of this premutation may themselves experience a wide range of clinical problems throughout their lifespan, the most severe being the late onset neurodegenerative condition called "Fragile X-Associated Tremor Ataxia Syndrome" (FXTAS), occurring between 8 and 16% of these carriers. Male premutation carriers, although they do not transmit expanded alleles to their daughters, have a much higher risk (40-50%) of developing FXTAS. Although this disorder is more prevalent and severe in male than female carriers, specific sex differences in clinical manifestations and progress of the FXTAS spectrum have been poorly documented. Here we compare the pattern and rate of progression (per year) in three motor scales including tremor/ataxia (ICARS), tremor (Clinical Tremor Rating scale, CRST), and parkinsonism (UPDRS), and in several cognitive and psychiatric tests scores, between 13 female and 9 male carriers initially having at least one of the motor scores ≥10. Moreover, we document the differences in each of the clinical and cognitive measures between the cross-sectional samples of 21 female and 24 male premutation carriers of comparable ages with FXTAS spectrum disorder (FSD), that is, who manifest one or more features of FXTAS. The results of progression assessment showed that it was more than twice the rate in male than in female carriers for the ICARS-both gait ataxia and kinetic tremor domains and twice as high in males on the CRST scale. In contrast, sex difference was negligible for the rate of progress in UPDRS, and all the cognitive measures. The overall psychiatric pathology score (SCL-90), as well as Anxiety and Obsessive/Compulsive domain scores, showed a significant increase only in the female sample. The pattern of sex differences for progression in motor scores was consistent with the results of comparison between larger, cross-sectional samples of male and female carriers affected with the FSD. These results were in concert with sex-specific distribution of MRI T2 white matter hyperintensities: all males, but no females, showed the middle cerebellar peduncle white matter hyperintensities (MCP sign), although the distribution and severity of these hyperintensities in the other brain regions were not dissimilar between the two sexes. In conclusion, the magnitude and specific pattern of sex differences in manifestations and progression of clinically recorded changes in motor performance and MRI lesion distribution support, on clinical grounds, the possibility of certain sex-limited factor(s) which, beyond the predictable effect of the second, normal FMR1 alleles in female premutation carriers, may have neuroprotective effects, specifically concerning the cerebellar circuitry.
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Affiliation(s)
- Danuta Z. Loesch
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Bundoora, VIC, Australia
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
- MIND Institute, University of California Davis Medical Center, Davis, CA, United States
| | - Anna Atkinson
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Bundoora, VIC, Australia
| | - Paige Stimpson
- Wellness and Recovery Centre, Monash Medical Centre, Clayton, VIC, Australia
| | - Nicholas Trost
- Medical Imaging Department, St Vincent's Hospital, University of Melbourne, Parkville, VIC, Australia
| | - Dean L. Pountney
- Neurodegeneration Research Group, School of Medical Science, Griffith University, Gold Coast Campus, Southport, NC, Australia
| | - Elsdon Storey
- Department of Medicine (Neuroscience), Monash University, Alfred Hospital Campus, Melbourne, VIC, Australia
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Loesch DZ, Kemp BE, Bui MQ, Fisher PR, Allan CY, Sanislav O, Ngoei KRW, Atkinson A, Tassone F, Annesley SJ, Storey E. Cellular Bioenergetics and AMPK and TORC1 Signalling in Blood Lymphoblasts Are Biomarkers of Clinical Status in FMR1 Premutation Carriers. Front Psychiatry 2021; 12:747268. [PMID: 34880790 PMCID: PMC8645580 DOI: 10.3389/fpsyt.2021.747268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
Fragile X Associated Tremor/Ataxia Syndrome (FXTAS) is a neurodegenerative disorder affecting carriers of premutation alleles (PM) of the X-linked FMR1 gene, which contain CGG repeat expansions of 55-200 range in a non-coding region. This late-onset disorder is characterised by the presence of tremor/ataxia and cognitive decline, associated with the white matter lesions throughout the brain, especially involving the middle cerebellar peduncles. Nearly half of older male and ~ 20% of female PM carriers develop FXTAS. While there is evidence for mitochondrial dysfunction in neural and some peripheral tissues from FXTAS patients (though less obvious in the non-FXTAS PM carriers), the results from peripheral blood mononuclear cells (PBMC) are still controversial. Motor, cognitive, and neuropsychiatric impairments were correlated with measures of mitochondrial and non-mitochondrial respiratory activity, AMPK, and TORC1 cellular stress-sensing protein kinases, and CGG repeat size, in a sample of adult FXTAS male and female carriers. Moreover, the levels of these cellular measures, all derived from Epstein- Barr virus (EBV)- transformed and easily accessible blood lymphoblasts, were compared between the FXTAS (N = 23) and non-FXTAS (n = 30) subgroups, and with baseline data from 33 healthy non-carriers. A significant hyperactivity of cellular bioenergetics components as compared with the baseline data, more marked in the non-FXTAS PMs, was negatively correlated with repeat numbers at the lower end of the CGG-PM distribution. Significant associations of these components with motor impairment measures, including tremor-ataxia and parkinsonism, and neuropsychiatric changes, were prevalent in the FXTAS subgroup. Moreover, a striking elevation of AMPK activity, and a decrease in TORC1 levels, especially in the non-FXTAS carriers, were related to the size of CGG expansion. The bioenergetics changes in blood lymphoblasts are biomarkers of the clinical status of FMR1 carriers. The relationship between these changes and neurological involvement in the affected carriers suggests that brain bioenergetic alterations are reflected in this peripheral tissue. A possible neuroprotective role of stress sensing kinase, AMPK, in PM carriers, should be addressed in future longitudinal studies. A decreased level of TORC1-the mechanistic target of the rapamycin complex, suggests a possible future approach to therapy in FXTAS.
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Affiliation(s)
- Danuta Z Loesch
- School of Psychology and Public Health, La Trobe University, Bundoora, VA, Australia
| | - Bruce E Kemp
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VA, Australia.,St. Vincent's Institute of Medical Research and Department of Medicine, University of Melbourne, Fitzroy, VA, Australia
| | - Minh Q Bui
- Centre for Molecular, Environmental, Genetic and Analytic, Epidemiology, University of Melbourne, Parkville, VA, Australia
| | - Paul R Fisher
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VA, Australia
| | - Claire Y Allan
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VA, Australia
| | - Oana Sanislav
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VA, Australia
| | - Kevin R W Ngoei
- St. Vincent's Institute of Medical Research and Department of Medicine, University of Melbourne, Fitzroy, VA, Australia
| | - Anna Atkinson
- School of Psychology and Public Health, La Trobe University, Bundoora, VA, Australia
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, United States.,Department of Biochemistry and Molecular Medicine M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, CA, United States
| | - Sarah J Annesley
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VA, Australia
| | - Elsdon Storey
- Department of Medicine (Neuroscience), Monash University, Alfred Hospital Campus, Melbourne, VIC, Australia
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Schneider A, Summers S, Tassone F, Seritan A, Hessl D, Hagerman P, Hagerman R. Women with Fragile X-associated Tremor/Ataxia Syndrome. Mov Disord Clin Pract 2020; 7:910-919. [PMID: 33163562 PMCID: PMC7604678 DOI: 10.1002/mdc3.13084] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/16/2020] [Accepted: 08/03/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Fragile X-associated tremor and ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder linked to the FMR1 premutation. OBJECTIVES FXTAS in women is far less common than in men, and this study represents the largest sample reported to date. METHODS A total of 53 female premutation carriers with FXTAS (meanage, 66.83 years; FXTAS stages 2-5) and 55 age-matched and demographic background-matched control participants (meanage, 61.94 years) underwent a comprehensive molecular, physiological, neuropsychological, and psychiatric assessment. RESULTS The large sample of female premutation carriers showed a wide range of variability of clinical signs and symptom progression. The imaging results showed a middle cerebellar peduncles sign in only 6 patients; another symptom included high-signal intensity in the splenium of the corpus callosum, and diffuse cerebral deep white matter changes (e.g., in the pons) are more common. The rate of psychiatric disorders, especially depression, is higher than in the general population. There is a clear impairment in executive functioning and fine motor skills in connection with a higher FXTAS stage. CONCLUSIONS The manifestation of FXTAS symptoms in female carriers can be diverse with a milder phenotype and a lower penetrance than those observed in male premutation carriers. The middle cerebellar peduncles sign is present in only a small percentage of the sample, and we propose that the imaging criteria for FXTAS in women need to be expanded.
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Affiliation(s)
- Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders InstituteSacramentoCaliforniaUSA
- Department of Pediatrics, School of MedicineUniversity of California–Davis, Medical CenterSacramentoCaliforniaUSA
| | - Scott Summers
- Department of Psychiatry and Behavioral SciencesUniversity of California–Davis, Medical CenterSacramentoCaliforniaUSA
| | - Flora Tassone
- Department of BiochemistryUniversity of California–Davis, Medical CenterSacramentoCaliforniaUSA
| | - Andreea Seritan
- Department of Psychiatry, UCSF Weill Institute for NeurosciencesUniversity of CaliforniaSan FranciscoCaliforniaUSA
| | - David Hessl
- Medical Investigation of Neurodevelopmental Disorders InstituteSacramentoCaliforniaUSA
- Department of Psychiatry and Behavioral SciencesUniversity of California–Davis, Medical CenterSacramentoCaliforniaUSA
| | - Paul Hagerman
- Department of BiochemistryUniversity of California–Davis, Medical CenterSacramentoCaliforniaUSA
| | - Randi Hagerman
- Medical Investigation of Neurodevelopmental Disorders InstituteSacramentoCaliforniaUSA
- Department of Pediatrics, School of MedicineUniversity of California–Davis, Medical CenterSacramentoCaliforniaUSA
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Prieto M, Folci A, Martin S. Post-translational modifications of the Fragile X Mental Retardation Protein in neuronal function and dysfunction. Mol Psychiatry 2020; 25:1688-1703. [PMID: 31822816 DOI: 10.1038/s41380-019-0629-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/22/2019] [Accepted: 11/27/2019] [Indexed: 12/17/2022]
Abstract
The Fragile X Mental Retardation Protein (FMRP) is an RNA-binding protein essential to the regulation of local translation at synapses. In the mammalian brain, synapses are constantly formed and eliminated throughout development to achieve functional neuronal networks. At the molecular level, thousands of proteins cooperate to accomplish efficient neuronal communication. Therefore, synaptic protein levels and their functional interactions need to be tightly regulated. FMRP generally acts as a translational repressor of its mRNA targets. FMRP is the target of several post-translational modifications (PTMs) that dynamically regulate its function. Here we provide an overview of the PTMs controlling the FMRP function and discuss how their spatiotemporal interplay contributes to the physiological regulation of FMRP. Importantly, FMRP loss-of-function leads to Fragile X syndrome (FXS), a rare genetic developmental condition causing a range of neurological alterations including intellectual disability (ID), learning and memory impairments, autistic-like features and seizures. Here, we also explore the possibility that recently reported missense mutations in the FMR1 gene disrupt the PTM homoeostasis of FMRP, thus participating in the aetiology of FXS. This suggests that the pharmacological targeting of PTMs may be a promising strategy to develop innovative therapies for patients carrying such missense mutations.
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Affiliation(s)
- Marta Prieto
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France
| | | | - Stéphane Martin
- Université Côte d'Azur, INSERM, CNRS, IPMC, Valbonne, France.
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8
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Lalonde E, Rentas S, Lin F, Dulik MC, Skraban CM, Spinner NB. Genomic Diagnosis for Pediatric Disorders: Revolution and Evolution. Front Pediatr 2020; 8:373. [PMID: 32733828 PMCID: PMC7360789 DOI: 10.3389/fped.2020.00373] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 06/02/2020] [Indexed: 12/14/2022] Open
Abstract
Powerful, recent advances in technologies to analyze the genome have had a profound impact on the practice of medical genetics, both in the laboratory and in the clinic. Increasing utilization of genome-wide testing such as chromosomal microarray analysis and exome sequencing have lead a shift toward a "genotype-first" approach. Numerous techniques are now available to diagnose a particular syndrome or phenotype, and while traditional techniques remain efficient tools in certain situations, higher-throughput technologies have become the de facto laboratory tool for diagnosis of most conditions. However, selecting the right assay or technology is challenging, and the wrong choice may lead to prolonged time to diagnosis, or even a missed diagnosis. In this review, we will discuss current core technologies for the diagnosis of classic genetic disorders to shed light on the benefits and disadvantages of these strategies, including diagnostic efficiency, variant interpretation, and secondary findings. Finally, we review upcoming technologies posed to impart further changes in the field of genetic diagnostics as we move toward "genome-first" practice.
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Affiliation(s)
- Emilie Lalonde
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Stefan Rentas
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Fumin Lin
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Matthew C. Dulik
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Cara M. Skraban
- Division of Human Genetics, Department of Pediatrics, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Nancy B. Spinner
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
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9
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Elevated FMR1-mRNA and lowered FMRP - A double-hit mechanism for psychiatric features in men with FMR1 premutations. Transl Psychiatry 2020; 10:205. [PMID: 32576818 PMCID: PMC7311546 DOI: 10.1038/s41398-020-00863-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 01/07/2023] Open
Abstract
Fragile X syndrome (FXS) is caused by a full mutation of the FMR1 gene (>200 CGG repeats and subsequent methylation), such that there is little or no FMR1 protein (FMRP) produced, leading to intellectual disability (ID). Individuals with the premutation allele (55-200 CGG repeats, generally unmethylated) have elevated FMR1 mRNA levels, a consequence of enhanced transcription, resulting in neuronal toxicity and a spectrum of premutation-associated disorders, including the neurodegenerative disorder fragile X-associated tremor/ataxia syndrome (FXTAS). Here we described 14 patients who had both lowered FMRP and elevated FMR1 mRNA levels, representing dual mechanisms of clinical involvement, which may combine features of both FXS and FXTAS. In addition, the majority of these cases show psychiatric symptoms, including bipolar disorder, and/or psychotic features, which are rarely seen in those with just FXS.
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10
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Merikangas AK, Almasy L. Using the tools of genetic epidemiology to understand sex differences in neuropsychiatric disorders. GENES BRAIN AND BEHAVIOR 2020; 19:e12660. [PMID: 32348611 PMCID: PMC7507200 DOI: 10.1111/gbb.12660] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 03/01/2020] [Accepted: 04/24/2020] [Indexed: 02/06/2023]
Abstract
Many neuropsychiatric disorders exhibit differences in prevalence, age of onset, symptoms or course of illness between males and females. For the most part, the origins of these differences are not well understood. In this article, we provide an overview of sex differences in psychiatric disorders including autism spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD), anxiety, depression, alcohol and substance abuse, schizophrenia, eating disorders and risk of suicide. We discuss both genetic and nongenetic mechanisms that have been hypothesized to underlie these differences, including ascertainment bias, environmental stressors, X‐ or Y‐linked risk loci, and differential liability thresholds in males and females. We then review the use of twin, family and genome‐wide association approaches to study potential genetic mechanisms of sex differences and the extent to which these designs have been employed in studies of psychiatric disorders. We describe the utility of genetic epidemiologic study designs, including classical twin and family studies, large‐scale studies of population registries, derived recurrence risks, and molecular genetic analyses of genome‐wide variation that may enhance our understanding sex differences in neuropsychiatric disorders.
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Affiliation(s)
- Alison K Merikangas
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Penn-CHOP Lifespan Brain Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Laura Almasy
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Penn-CHOP Lifespan Brain Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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11
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Nourse J, Spada S, Danckwardt S. Emerging Roles of RNA 3'-end Cleavage and Polyadenylation in Pathogenesis, Diagnosis and Therapy of Human Disorders. Biomolecules 2020; 10:biom10060915. [PMID: 32560344 PMCID: PMC7356254 DOI: 10.3390/biom10060915] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/10/2020] [Accepted: 06/13/2020] [Indexed: 12/11/2022] Open
Abstract
A crucial feature of gene expression involves RNA processing to produce 3′ ends through a process termed 3′ end cleavage and polyadenylation (CPA). This ensures the nascent RNA molecule can exit the nucleus and be translated to ultimately give rise to a protein which can execute a function. Further, alternative polyadenylation (APA) can produce distinct transcript isoforms, profoundly expanding the complexity of the transcriptome. CPA is carried out by multi-component protein complexes interacting with multiple RNA motifs and is tightly coupled to transcription, other steps of RNA processing, and even epigenetic modifications. CPA and APA contribute to the maintenance of a multitude of diverse physiological processes. It is therefore not surprising that disruptions of CPA and APA can lead to devastating disorders. Here, we review potential CPA and APA mechanisms involving both loss and gain of function that can have tremendous impacts on health and disease. Ultimately we highlight the emerging diagnostic and therapeutic potential CPA and APA offer.
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Affiliation(s)
- Jamie Nourse
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany; (J.N.); (S.S.)
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
| | - Stefano Spada
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany; (J.N.); (S.S.)
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
| | - Sven Danckwardt
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany; (J.N.); (S.S.)
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Rhine-Main, Germany
- Correspondence:
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12
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Hawkins E, Akarca D, Zhang M, Brkić D, Woolrich M, Baker K, Astle D. Functional network dynamics in a neurodevelopmental disorder of known genetic origin. Hum Brain Mapp 2019; 41:530-544. [PMID: 31639257 PMCID: PMC7268087 DOI: 10.1002/hbm.24820] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 08/17/2019] [Accepted: 09/30/2019] [Indexed: 01/03/2023] Open
Abstract
Dynamic connectivity in functional brain networks is a fundamental aspect of cognitive development, but we have little understanding of the mechanisms driving variability in these networks. Genes are likely to influence the emergence of fast network connectivity via their regulation of neuronal processes, but novel methods to capture these rapid dynamics have rarely been used in genetic populations. The current study redressed this by investigating brain network dynamics in a neurodevelopmental disorder of known genetic origin, by comparing individuals with a ZDHHC9-associated intellectual disability to individuals with no known impairment. We characterised transient network dynamics using a Hidden Markov Model (HMM) on magnetoencephalography (MEG) data, at rest and during auditory oddball stimulation. The HMM is a data-driven method that captures rapid patterns of coordinated brain activity recurring over time. Resting-state network dynamics distinguished the groups, with ZDHHC9 participants showing longer state activation and, crucially, ZDHHC9 gene expression levels predicted the group differences in dynamic connectivity across networks. In contrast, network dynamics during auditory oddball stimulation did not show this association. We demonstrate a link between regional gene expression and brain network dynamics, and present the new application of a powerful method for understanding the neural mechanisms linking genetic variation to cognitive difficulties.
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Affiliation(s)
- Erin Hawkins
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Danyal Akarca
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Mengya Zhang
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Diandra Brkić
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Mark Woolrich
- Oxford Centre for Human Brain Activity, University of Oxford, University Department of Psychiatry, Warneford Hospital, Oxford, UK
| | - Kate Baker
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK.,Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Cambridge, UK
| | - Duncan Astle
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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13
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Movaghar A, Page D, Brilliant M, Baker MW, Greenberg J, Hong J, DaWalt LS, Saha K, Kuusisto F, Stewart R, Berry-Kravis E, Mailick MR. Data-driven phenotype discovery of FMR1 premutation carriers in a population-based sample. SCIENCE ADVANCES 2019; 5:eaaw7195. [PMID: 31457090 PMCID: PMC6703870 DOI: 10.1126/sciadv.aaw7195] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/15/2019] [Indexed: 05/18/2023]
Abstract
The impact of the FMR1 premutation on human health is the subject of considerable controversy. A fundamental unanswered question is whether carrying the premutation allele is directly correlated with clinical phenotypes. A challenging problem in past genotype-phenotype studies of the FMR1 premutation is ascertainment bias, which could lead to invalid research conclusions and negatively affect clinical practice. Here, we created the first population-based FMR1-informed biobank to find the pattern of health characteristics in premutation carriers. Our extensive phenotyping shows that premutation carriers experience a clinical profile that is significantly different from controls and is evident throughout adulthood. Comprehensive understanding of the clinical risk associated with this genetic variant is critical for premutation carriers, their families, and clinicians and has important implications for public health.
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Affiliation(s)
- Arezoo Movaghar
- Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, USA
| | - David Page
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, WI, USA
| | | | | | - Jan Greenberg
- Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
| | - Jinkuk Hong
- Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
| | | | - Krishanu Saha
- Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, USA
| | | | - Ron Stewart
- Morgridge Institute for Research, Madison, WI, USA
| | | | - Marsha R. Mailick
- Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
- Corresponding author.
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14
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Nayar K, McKinney W, Hogan AL, Martin GE, La Valle C, Sharp K, Berry-Kravis E, Norton ES, Gordon PC, Losh M. Language processing skills linked to FMR1 variation: A study of gaze-language coordination during rapid automatized naming among women with the FMR1 premutation. PLoS One 2019; 14:e0219924. [PMID: 31348790 PMCID: PMC6660192 DOI: 10.1371/journal.pone.0219924] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 07/03/2019] [Indexed: 01/15/2023] Open
Abstract
The FMR1 premutation (PM) is relatively common in the general population. Evidence suggests that PM carriers may exhibit subtle differences in specific cognitive and language abilities. This study examined potential mechanisms underlying such differences through the study of gaze and language coordination during a language processing task (rapid automatized naming; RAN) among female carriers of the FMR1 PM. RAN taps a complex set of underlying neuropsychological mechanisms, with breakdowns implicating processing disruptions in fundamental skills that support higher order language and executive functions, making RAN (and analysis of gaze/language coordination during RAN) a potentially powerful paradigm for revealing the phenotypic expression of the FMR1 PM. Forty-eight PM carriers and 56 controls completed RAN on an eye tracker, where they serially named arrays of numbers, letters, colors, and objects. Findings revealed a pattern of inefficient language processing in the PM group, including a greater number of eye fixations (namely, visual regressions) and reduced eye-voice span (i.e., the eyes' lead over the voice) relative to controls. Differences were driven by performance in the latter half of the RAN arrays, when working memory and processing load are the greatest, implicating executive skills. RAN deficits were associated with broader social-communicative difficulties among PM carriers, and with FMR1-related molecular genetic variation (higher CGG repeat length, lower activation ratio, and increased levels of the fragile X mental retardation protein; FMRP). Findings contribute to an understanding of the neurocognitive profile of PM carriers and indicate specific gene-behavior associations that implicate the role of the FMR1 gene in language-related processes.
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Affiliation(s)
- Kritika Nayar
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
| | - Walker McKinney
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
- Clinical Child Psychology Program, University of Kansas, Lawrence, Kansas, United States of America
| | - Abigail L. Hogan
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
- Psychology, University of South Carolina, Columbia, South Carolina, United States of America
| | - Gary E. Martin
- St. John’s University, Communication Sciences and Disorders, Queens, New York, United States of America
| | - Chelsea La Valle
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
- Psychology, Boston University, Boston, Massachusetts, United States of America
| | - Kevin Sharp
- Pediatrics, Rush University Medical Center, Chicago, Illinois, United States of America
| | | | - Elizabeth S. Norton
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
| | - Peter C. Gordon
- Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
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15
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Tan MM, Dy JB, Salcedo-Arellano MJ, Tassone F, Hagerman RJ. Fragile X- associated Neuropsychiatric Disorders: A Case Report. FUTURE NEUROLOGY 2019; 14:10.2217/fnl-2018-0040. [PMID: 32089651 PMCID: PMC7034938 DOI: 10.2217/fnl-2018-0040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mutations in the Fragile X Mental Retardation 1 (FMR1) gene create a spectrum of developmental disorders in children in addition to neurodegenerative problems in older populations. Two types of mutations are recognized in the FMR1 gene. The full mutation (>200 CGG repeats) in the FMR1 gene leads to Fragile X Syndrome which is the most common inherited cause of intellectual disability and autism, while the premutation (55 to 200 CGG repeats) identified among carriers leads to a range of problems linked to elevated levels of the FMR1 mRNA leading to mRNA toxicity and occasionally mildly deficient FMRP levels. Two disorders among premutation carriers have been recognized namely: the Fragile X-associated Primary Ovarian Insufficiency (FXPOI) and Fragile X-associated Tremor/Ataxia Syndrome (FXTAS). Recently, in order to recognize a group of associated disorders commonly found in premutation carriers and extensively reported in co-morbidities studies, a new distinctive name was proposed: Fragile X-associated Neuropsychiatric Disorders (FXAND). This paper will present a case report of a female premutation carrier who has encountered predominantly psychiatric problems, but also chronic pain and sleep disturbances consistent with FXAND.
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Affiliation(s)
- Maria Melinda Tan
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health, Sacramento, CA, USA
- MedMom Institute for Human Development, Pasig City, Philippines
- Department of Psychology, University of the Philippines Diliman, Quezon City, Philippines
| | - Jeanne Barbara Dy
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health, Sacramento, CA, USA
- MedMom Institute for Human Development, Pasig City, Philippines
- Department of Pediatrics, The Medical City, Ortigas Avenue, Pasig City, Philippines
| | - Maria Jimena Salcedo-Arellano
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health, Sacramento, CA, USA
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health, Sacramento, CA, USA
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, California
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health, Sacramento, CA, USA
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, USA
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16
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Salcedo-Arellano MJ, Hagerman RJ, Martínez-Cerdeño V. [Fragile X associated tremor/ataxia syndrome: its clinical presentation, pathology, and treatment]. Rev Neurol 2019; 68:199-206. [PMID: 30805918 PMCID: PMC7001878 DOI: 10.33588/rn.6805.2018457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fragile X associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disease associated with the repetition of CGG triplets (55-200 CGG repetitions) in the FMR1 gene. The premutation of the FMR1 gene, contrasting with the full mutation (more than 200 CGG repetitions), presents an increased production of messenger and a similar or slightly decreased production of FMRP protein. FXTAS affects 40% of men and 16% of women carriers of the premutation. It presents with a wide constellation of neurological signs such as intention tremor, cerebellar ataxia, parkinsonism, executive function deficits, peripheral neuropathy and cognitive decline leading to dementia among others. In this review, we present what is currently known about the molecular mechanism, the radiological findings and the pathology, as well as the complexity of the diagnosis and management of FXTAS.
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Affiliation(s)
- María Jimena Salcedo-Arellano
- Department of Pediatrics, University of California Davis
School of Medicine, Sacramento, CA, USA
- Medical Investigation of Neurodevelopmental Disorders
(MIND) Institute, University of California Davis, Sacramento, CA, USA
| | - Randi J Hagerman
- Department of Pediatrics, University of California Davis
School of Medicine, Sacramento, CA, USA
- Medical Investigation of Neurodevelopmental Disorders
(MIND) Institute, University of California Davis, Sacramento, CA, USA
| | - Verónica Martínez-Cerdeño
- Medical Investigation of Neurodevelopmental Disorders
(MIND) Institute, University of California Davis, Sacramento, CA, USA
- Institute for Pediatric Regenerative Medicine and Shriners
Hospitals for Children Northern California, Sacramento, CA, USA
- Department of Pathology and Laboratory Medicine, UC Davis
School of Medicine, Sacramento, CA, USA
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17
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Hagerman RJ, Protic D, Rajaratnam A, Salcedo-Arellano MJ, Aydin EY, Schneider A. Fragile X-Associated Neuropsychiatric Disorders (FXAND). Front Psychiatry 2018; 9:564. [PMID: 30483160 PMCID: PMC6243096 DOI: 10.3389/fpsyt.2018.00564] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/18/2018] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS) is caused by the full mutation (>200 CGG repeats) in the Fragile X Mental Retardation 1 (FMR1) gene. It is the most common inherited cause of intellectual disability (ID) and autism. This review focuses on neuropsychiatric disorders frequently experienced by premutation carriers with 55 to 200 CGG repeats and the pathophysiology involves elevated FMR1 mRNA levels, which is different from the absence or deficiency of fragile X mental retardation protein (FMRP) seen in FXS. Neuropsychiatric disorders are the most common problems associated with the premutation, and they affect approximately 50% of individuals with 55 to 200 CGG repeats in the FMR1 gene. Neuropsychiatric disorders in children with the premutation include anxiety, ADHD, social deficits, or autism spectrum disorders (ASD). In adults with the premutation, anxiety and depression are the most common problems, although obsessive compulsive disorder, ADHD, and substance abuse are also common. These problems are often exacerbated by chronic fatigue, chronic pain, fibromyalgia, autoimmune disorders and sleep problems, which are also associated with the premutation. Here we review the clinical studies, neuropathology and molecular underpinnings of RNA toxicity associated with the premutation. We also propose the name Fragile X-associated Neuropsychiatric Disorders (FXAND) in an effort to promote research and the use of fragile X DNA testing to enhance recognition and treatment for these disorders.
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Affiliation(s)
- Randi J. Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Sacramento, CA, United States
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, United States
| | - Dragana Protic
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Sacramento, CA, United States
- Department of Pharmacology, Clinical Pharmacology and Toxicology, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Akash Rajaratnam
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Sacramento, CA, United States
- Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Maria J. Salcedo-Arellano
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Sacramento, CA, United States
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, United States
| | - Elber Yuksel Aydin
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Sacramento, CA, United States
- Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Sacramento, CA, United States
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, United States
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18
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Bathelt J, Barnes J, Raymond FL, Baker K, Astle D. Global and Local Connectivity Differences Converge With Gene Expression in a Neurodevelopmental Disorder of Known Genetic Origin. Cereb Cortex 2018; 27:3806-3817. [PMID: 28168288 PMCID: PMC6600876 DOI: 10.1093/cercor/bhx027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 01/19/2017] [Indexed: 11/26/2022] Open
Abstract
Knowledge of genetic cause in neurodevelopmental disorders can highlight molecular and cellular processes critical for typical development. Furthermore, the relative homogeneity of neurodevelopmental disorders of known genetic origin allows the researcher to establish the subsequent neurobiological processes that mediate cognitive and behavioral outcomes. The current study investigated white matter structural connectivity in a group of individuals with intellectual disability due to mutations in ZDHHC9. In addition to shared cause of cognitive impairment, these individuals have a shared cognitive profile, involving oromotor control difficulties and expressive language impairment. Analysis of structural network properties using graph theory measures showed global reductions in mean clustering coefficient and efficiency in the ZDHHC9 group, with maximal differences in frontal and parietal areas. Regional variation in clustering coefficient across cortical regions in ZDHHC9 mutation cases was significantly associated with known pattern of expression of ZDHHC9 in the normal adult human brain. The results demonstrate that a mutation in a single gene impacts upon white matter organization across the whole-brain, but also shows regionally specific effects, according to variation in gene expression. Furthermore, these regionally specific patterns may link to specific developmental mechanisms, and correspond to specific cognitive deficits.
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Affiliation(s)
- Joe Bathelt
- MRC Cognition & Brain Sciences Unit, Cambridge CB2 7EF, UK
| | - Jessica Barnes
- MRC Cognition & Brain Sciences Unit, Cambridge CB2 7EF, UK
| | - F Lucy Raymond
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Kate Baker
- MRC Cognition & Brain Sciences Unit, Cambridge CB2 7EF, UK.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Duncan Astle
- MRC Cognition & Brain Sciences Unit, Cambridge CB2 7EF, UK
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19
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Wheeler A, Raspa M, Hagerman R, Mailick M, Riley C. Implications of the FMR1 Premutation for Children, Adolescents, Adults, and Their Families. Pediatrics 2017; 139:S172-S182. [PMID: 28814538 PMCID: PMC5621635 DOI: 10.1542/peds.2016-1159d] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/24/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Given the nature of FMR1 gene expansions, most biological mothers, and often multiple other family members of children with fragile X syndrome (FXS), will have a premutation, which may increase individual and family vulnerabilities. This article summarizes important gaps in knowledge and notes potential implications for pediatric providers with regard to developmental and medical risks for children and adolescents with an FMR1 premutation, including possible implications into adulthood. METHODS A structured electronic literature search was conducted on FMR1 pre- and full mutations, yielding a total of 306 articles examined. Of these, 116 focused primarily on the premutation and are included in this review. RESULTS Based on the literature review, 5 topic areas are discussed: genetics and epidemiology; phenotypic characteristics of individuals with the premutation; implications for carrier parents of children with FXS; implications for the extended family; and implications for pediatricians. CONCLUSIONS Although the premutation phenotype is typically less severe in clinical presentation than in FXS, premutation carriers are much more common and are therefore more likely to be seen in a typical pediatric practice. In addition, there is a wide range of medical, cognitive/developmental, and psychiatric associated features that individuals with a premutation are at increased risk for having, which underscores the importance of awareness on the part of pediatricians in identifying and monitoring premutation carriers and recognizing the impact this identification may have on family members.
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Affiliation(s)
- Anne Wheeler
- RTI International, Research Triangle Park, North Carolina;
| | - Melissa Raspa
- RTI International, Research Triangle Park, North Carolina
| | - Randi Hagerman
- MIND Institute, University of California at Davis, Sacramento, California
| | - Marsha Mailick
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Catharine Riley
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
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20
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Jiraanont P, Sweha SR, AlOlaby RR, Silva M, Tang HT, Durbin-Johnson B, Schneider A, Espinal GM, Hagerman PJ, Rivera SM, Hessl D, Hagerman RJ, Chutabhakdikul N, Tassone F. Clinical and molecular correlates in fragile X premutation females. eNeurologicalSci 2017; 7:49-56. [PMID: 28971146 PMCID: PMC5621595 DOI: 10.1016/j.ensci.2017.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 04/10/2017] [Indexed: 12/21/2022] Open
Abstract
The prevalence of the fragile X premutation (55-200 CGG repeats) among the general population is relatively high, but there remains a lack of clear understanding of the links between molecular biomarkers and clinical outcomes. In this study we investigated the correlations between molecular measures (CGG repeat size, FMR1 mRNA, FMRP expression levels, and methylation status at the promoter region and in FREE2 site) and clinical phenotypes (anxiety, obsessive compulsive symptoms, depression and executive function deficits) in 36 adult premutation female carriers and compared to 24 normal control subjects. Premutation carriers reported higher levels of obsessive compulsive symptoms, depression, and anxiety, but demonstrated no significant deficits in global cognitive functions or executive function compared to the control group. Increased age in carriers was significantly associated with increased anxiety levels. As expected, FMR1 mRNA expression was significantly correlated with CGG repeat number. However, no significant correlations were observed between molecular (including epigenetic) measures and clinical phenotypes in this sample. Our study, albeit limited by the sample size, establishes the complexity of the mechanisms that link the FMR1 locus to the clinical phenotypes commonly observed in female carriers suggesting that other factors, including environment or additional genetic changes, may have an impact on the clinical phenotypes. However, it continues to emphasize the need for assessment and treatment of psychiatric problems in female premutation carriers.
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Affiliation(s)
- Poonnada Jiraanont
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand
| | - Stefan R. Sweha
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
| | - Reem R. AlOlaby
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
| | - Marisol Silva
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
| | - Hiu-Tung Tang
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
| | - Blythe Durbin-Johnson
- Department of Public Health Sciences, School of Medicine, University of California at Davis, Davis, CA, USA
| | - Andrea Schneider
- Department of Pediatrics, School of Medicine, University of California Davis, Davis, CA, USA
- MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
| | - Glenda M. Espinal
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
| | - Paul J. Hagerman
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
- MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
| | - Susan M. Rivera
- MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
- Neurocognitive Development Lab, Center for Mind and Brain UC Davis, Professor, Department of Psychology, University of California Davis Medical Center, Sacramento, CA, USA
| | - David Hessl
- MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, CA, USA
| | - Randi J. Hagerman
- Department of Pediatrics, School of Medicine, University of California Davis, Davis, CA, USA
- MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
| | - Nuanchan Chutabhakdikul
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, CA, USA
- MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
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21
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Kong HE, Zhao J, Xu S, Jin P, Jin Y. Fragile X-Associated Tremor/Ataxia Syndrome: From Molecular Pathogenesis to Development of Therapeutics. Front Cell Neurosci 2017; 11:128. [PMID: 28529475 PMCID: PMC5418347 DOI: 10.3389/fncel.2017.00128] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/18/2017] [Indexed: 12/31/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by a premutation CGG repeat expansion (55-200 repeats) within the 5' UTR of the fragile X gene (FMR1). FXTAS is characterized by intension tremor, cerebellar ataxia, progressive neurodegeneration, parkinsonism and cognitive decline. The development of transgenic mouse and Drosophila melanogaster models carrying an expanded CGG repeat has yielded valuable insight into the pathophysiology of FXTAS. To date, we know of two main molecular mechanisms of this disorder: (1) a toxic gain of function of the expanded CGG-repeat FMR1 mRNA, which results in the binding/sequestration of the CGG-binding proteins; and (2) CGG repeat-associated non-AUG-initiated (RAN) translation, which generates a polyglycine peptide toxic to cells. Besides these CGG-mediated mechanisms, recent studies have shed light on additional mechanisms of pathogenesis, such as the antisense transcript ASFMR1, mitochondrial dysfunction, DNA damage from R-loop formation and 5-hydroxymethylcytosine (5hmC)-mediated epigenetic modulation. Here we summarize the recent progress towards understanding the etiology of FXTAS and provide an overview of potential treatment strategies.
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Affiliation(s)
- Ha Eun Kong
- Department of Human Genetics, School of Medicine, Emory UniversityAtlanta, GA, USA
| | - Juan Zhao
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South UniversityChangsha, China
| | - Shunliang Xu
- Department of Neurology, 2nd Hospital of Shandong UniversityJinan, China
| | - Peng Jin
- Department of Human Genetics, School of Medicine, Emory UniversityAtlanta, GA, USA
| | - Yan Jin
- Department of Ophthalmology, Second Hospital, Jilin UniversityChangchun, China
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Fragile X premutation in women: recognizing the health challenges beyond primary ovarian insufficiency. J Assist Reprod Genet 2016; 34:315-323. [PMID: 27995424 DOI: 10.1007/s10815-016-0854-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 11/25/2016] [Indexed: 12/17/2022] Open
Abstract
Fragile X premutation carriers have 55-200 CGG repeats in the 5' untranslated region of the FMR1 gene. Women with this premutation face many physical and emotional challenges in their life. Approximately 20% of these women will develop fragile X-associated primary ovarian insufficiency (FXPOI). In addition, they suffer from increased rates of menstrual dysfunction, diminished ovarian reserve, reduction in age of menopause, infertility, dizygotic twinning, and risk of having an offspring with a premutation or full mutation. Consequent chronic hypoestrogenism may result in impaired bone health and increased cardiovascular risk. Neuropsychiatric issues include risk of developing fragile X-associated tremor/ataxia syndrome, neuropathy, musculoskeletal problems, increased prevalence of anxiety, depression, and sleep disturbances independent of the stress of raising an offspring with fragile X syndrome and higher risk of postpartum depression. Some studies have reported a higher prevalence of thyroid abnormalities and hypertension in these women. Reproductive health providers play an important role in the health supervision of women with fragile X premutation. Awareness of these risks and correlation of the various manifestations could help in early diagnosis and coordination of care and services for these women and their families. This paper reviews current evidence regarding the possible conditions that may present in women with premutation-sized repeats beyond FXPOI.
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Lozano R, Martinez-Cerdeno V, Hagerman RJ. Advances in the Understanding of the Gabaergic Neurobiology of FMR1 Expanded Alleles Leading to Targeted Treatments for Fragile X Spectrum Disorder. Curr Pharm Des 2016; 21:4972-4979. [PMID: 26365141 DOI: 10.2174/1381612821666150914121038] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022]
Abstract
Fragile X spectrum disorder (FXSD) includes: fragile X syndrome (FXS), fragile X-associated tremor ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI), as well as other medical, psychiatric and neurobehavioral problems associated with the premutation and gray zone alleles. FXS is the most common monogenetic cause of autism (ASD) and intellectual disability (ID). The understanding of the neurobiology of FXS has led to many targeted treatment trials in FXS. The first wave of phase II clinical trials in FXS were designed to target the mGluR5 pathway; however the results did not show significant efficacy and the trials were terminated. The advances in the understanding of the GABA system in FXS have shifted the focus of treatment trials to GABA agonists, and a new wave of promising clinical trials is under way. Ganaxolone and allopregnanolone (GABA agonists) have been studied in individuals with FXSD and are currently in phase II trials. Both allopregnanolone and ganaxolone may be efficacious in treatment of FXS and FXTAS, respectively. Allopregnanolone, ganaxolone, riluzole, gaboxadol, tiagabine, and vigabatrin are potential GABAergic treatments. The lessons learned from the initial trials have not only shifted the targeted system, but also have refined the design of clinical trials. The results of these new trials will likely impact further clinical trials for FXS and other genetic disorders associated with ASD.
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Affiliation(s)
- Reymundo Lozano
- Icahn School of Medicine at Mount Sinai, New York, NY USA; Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Veronica Martinez-Cerdeno
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospital for Children of Northern California, Sacramento, CA, USA; Department of Pathology and Laboratory Medicine, UC Davis, Sacramento, USA
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Department of Pediatrics, UC Davis, Sacramento, CA, USA
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Schneider A, Johnston C, Tassone F, Sansone S, Hagerman RJ, Ferrer E, Rivera SM, Hessl D. Broad autism spectrum and obsessive-compulsive symptoms in adults with the fragile X premutation. Clin Neuropsychol 2016; 30:929-43. [PMID: 27355445 DOI: 10.1080/13854046.2016.1189536] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Clinical observations and a limited number of research studies provide evidence that the fragile X premutation may confer risk for autism, executive dysfunction, and psychopathology. The link to autism spectrum symptoms and social cognition deficits with the premutation remains uncertain, and thus was the focus of the present investigation. METHOD Our sample included 131 individuals, 42 men/22 women with the FMR1 premutation (mean age = 31.83 ± 8.59 years) with a normal neurological exam, and 48 men/19 women healthy age-matched controls (mean age = 29.48 ± 7.29 years). Individuals completed a comprehensive neuropsychological battery with additional assessments for social cognition, broad autism spectrum, and obsessive-compulsive (OC) symptoms. RESULTS Premutation carriers self-reported higher rates of autism-related symptoms (Autism Quotient; p = .001). Among males only, premutation carriers showed more atypical social interaction (p < .001) and stereotyped behavior (p = .014) during standardized clinical examination on the Autism Diagnostic Observation Schedule (ADOS) relative to controls. Female premutation carriers reported significantly higher rates of OC symptoms compared to control females (p = .012). Molecular measures defining the expanded premutation (FMR1 CGG repeat length and/or mRNA) were significantly associated with a measure of theory of mind (Reading the Mind in the Eyes Task). CONCLUSIONS The results of this study indicate a higher rate of broad autism spectrum symptoms in some males with the premutation and provide evidence for an obsessive-compulsive subtype in female premutation carriers.
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Affiliation(s)
- A Schneider
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,c Department of Pediatrics , UC Davis School of Medicine , Sacramento , CA , USA
| | - C Johnston
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,b Department of Psychiatry and Behavioral Sciences , UC Davis School of Medicine , Sacramento , CA , USA
| | - F Tassone
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,f Department of Biochemistry and Molecular Medicine , UC Davis , Davis , CA , USA
| | - S Sansone
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,g Department of Human Development , UC Davis , Davis , CA , USA
| | - R J Hagerman
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,c Department of Pediatrics , UC Davis School of Medicine , Sacramento , CA , USA
| | - E Ferrer
- d Department of Psychology , UC Davis , Davis , CA , USA
| | - S M Rivera
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,d Department of Psychology , UC Davis , Davis , CA , USA.,e Center for Mind and Brain, UC Davis , Davis , CA , USA
| | - D Hessl
- a MIND Institute, UC Davis Medical Center , Sacramento , CA , USA.,b Department of Psychiatry and Behavioral Sciences , UC Davis School of Medicine , Sacramento , CA , USA
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Grigsby J. The fragile X mental retardation 1 gene (FMR1): historical perspective, phenotypes, mechanism, pathology, and epidemiology. Clin Neuropsychol 2016; 30:815-33. [PMID: 27356167 DOI: 10.1080/13854046.2016.1184652] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To provide an historical perspective and overview of the phenotypes, mechanism, pathology, and epidemiology of the fragile X-associated tremor/ataxia syndrome (FXTAS) for neuropsychologists. METHODS Selective review of the literature on FXTAS. RESULTS FXTAS is an X-linked neurodegenerative disorder of late onset. One of several phenotypes associated with different mutations of the fragile X mental retardation 1 gene (FMR1), FXTAS involves progressive action tremor, gait ataxia, and impaired executive functioning, among other features. It affects carriers of the FMR1 premutation, which may expand when passed from a mother to her children, in which case it is likely to cause fragile X syndrome (FXS), the most common inherited developmental disability. CONCLUSION This review briefly summarizes current knowledge of the mechanisms, epidemiology, and mode of transmission of FXTAS and FXS, as well as the neuropsychological, neurologic, neuropsychiatric, neuropathologic, and neuroradiologic phenotypes of FXTAS. Because it was only recently identified, FXTAS is not well known to most practitioners, and it remains largely misdiagnosed, despite the fact that its prevalence may be relatively high.
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Affiliation(s)
- Jim Grigsby
- a Departments of Psychology and Medicine , University of Colorado Denver , Denver , CO , USA
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Abstract
Many physicians are unaware of the many phenotypes associated with the fragile X premutation, an expansion in the 5' untranslated region of the fragile X mental retardation 1 (FMR1) gene that consists of 55-200 CGG repeats. The most severe of these phenotypes is fragile X-associated tremor/ataxia syndrome (FXTAS), which occurs in the majority of ageing male premutation carriers but in fewer than 20% of ageing women with the premutation. The prevalence of the premutation is 1 in 150-300 females, and 1 in 400-850 males, so physicians are likely to see people affected by FXTAS. Fragile X DNA testing is broadly available in the Western world. The clinical phenotype of FXTAS at presentation can vary and includes intention tremor, cerebellar ataxia, neuropathic pain, memory and/or executive function deficits, parkinsonian features, and psychological disorders, such as depression, anxiety and/or apathy. FXTAS causes brain atrophy and white matter disease, usually in the middle cerebellar peduncles, the periventricular area, and the splenium and/or genu of the corpus callosum. Here, we review the complexities involved in the clinical management of FXTAS and consider how targeted treatment for these clinical features of FXTAS will result from advances in our understanding of the molecular mechanisms that underlie this neurodegenerative disorder. Such targeted approaches should also be more broadly applicable to earlier forms of clinical involvement among premutation carriers.
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27
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Synaptic Plasticity, a Prominent Contributor to the Anxiety in Fragile X Syndrome. Neural Plast 2016; 2016:9353929. [PMID: 27239350 PMCID: PMC4864533 DOI: 10.1155/2016/9353929] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 04/04/2016] [Indexed: 01/03/2023] Open
Abstract
Fragile X syndrome (FXS) is an inheritable neuropsychological disease caused by expansion of the CGG trinucleotide repeat affecting the fmr1 gene on X chromosome, resulting in silence of the fmr1 gene and failed expression of FMRP. Patients with FXS suffer from cognitive impairment, sensory integration deficits, learning disability, anxiety, autistic traits, and so forth. Specifically, the morbidity of anxiety in FXS individuals remains high from childhood to adulthood. By and large, it is common that the change of brain plasticity plays a key role in the progression of disease. But for now, most studies excessively emphasized the one-sided factor on the change of synaptic plasticity participating in the generation of anxiety during the development of FXS. Here we proposed an integrated concept to acquire better recognition about the details of this process.
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Abstract
There is empirical evidence for a role for serotonin in autism . In experimental animals, early life exposure to serotonergic antidepressants or maternal stress affects brain development, with subsequent changes in serotonin tone in adult animals. Recently, antidepressant exposure during pregnancy has been associated with autism in epidemiological studies. At least part of the association is potentially explained by maternal depression or factors associated with depression. Importantly, even if there is no causal relation between prenatal antidepressant exposure and autism, use of antidepressants during pregnancy is a marker of potential problems later in life across five independent study populations, and exposed children may need special attention regardless of the underlying mechanism. Future studies need to disentangle the effects of maternal depression and antidepressant use during pregnancy while adjusting for the postnatal environment. One promising strategy is to use results from basic science to guide the inclusion of potential biological intermediates in advanced epidemiological studies.
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Winarni TI, Schneider A, Ghaziuddin N, Seritan A, Hagerman RJ. Psychosis and catatonia in fragile X: Case report and literature review. Intractable Rare Dis Res 2015; 4:139-46. [PMID: 26361565 PMCID: PMC4561243 DOI: 10.5582/irdr.2015.01028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 07/31/2015] [Accepted: 08/12/2015] [Indexed: 12/13/2022] Open
Abstract
Fragile X mental retardation 1 (FMR1) premutation associated phenotypes have been explored extensively since the molecular mechanism emerged involving elevated FMR1 messenger ribonucleic acid (mRNA) levels. Lowered fragile X mental retardation protein (FMRP) can also occur which may have an additive effect to the high levels of mRNA leading to neurodevelopmental problems and psychopathology. This paper was aimed to review psychosis and catatonia in premutation carriers, express the role of elevated FMR1 mRNA and lowered FMRP in the phenotype of carriers and present a case of psychosis and catatonia in a carrier. This case also demonstrates additional genetic and environmental factors which may also affect the phenotype. We review the literature and report an exemplary case of a 25 year old male premutation carrier with elevated FMR1 mRNA, low FMRP, a cytochrome P450 family 2 subfamily D polypeptide 6 (CYP2D6)*2xN mutation and a perinatal insult. This patient developed an autism spectrum disorder, psychosis, catatonia with subsequent cognitive decline after electro-convulsive therapy (ECT) for his catatonia. He had a premutation of 72 CGG repeat in FMR1, FMR1 mRNA level that was over 2.4 times normal and FMRP level at 18% of normal, and additionally, a CYP2D6 allelic variant which leads to ultrarapid metabolism (UM) of medication. There is an overlapping pathophysiological mechanism of catatonia and fragile X-associated premutation phenotypes including autism and psychosis. This case demonstrates the shared phenotype and the overlap of the pathophysiological mechanisms that can influence the intervention. Multiple genetic and environmental hits can lead to more significant involvement in premutation carriers.
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Affiliation(s)
- Tri Indah Winarni
- MIND Institute, University of California Davis, Medical Center, Sacramento, USA
- Center for Biomedical Research (CEBIOR), Faculty of Medicine Diponegoro University, Semarang, Indonesia
| | - Andrea Schneider
- MIND Institute, University of California Davis, Medical Center, Sacramento, USA
- Department of Pediatrics, University of California Davis, Medical Center, Sacramento, USA
| | - Neera Ghaziuddin
- University of Michigan Hospitals and Health Center, Ann Arbor, USA
| | - Andreea Seritan
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Medical Center, Sacramento, USA
| | - Randi J Hagerman
- MIND Institute, University of California Davis, Medical Center, Sacramento, USA
- Department of Pediatrics, University of California Davis, Medical Center, Sacramento, USA
- Address correspondence to: Dr. Randi J. Hagerman, MIND Institute, UC Davis Health System, 2825 50th Street, Sacramento, CA 95817, USA. E-mail:
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Hagerman PJ, Hagerman RJ. Fragile X-associated tremor/ataxia syndrome. Ann N Y Acad Sci 2015; 1338:58-70. [PMID: 25622649 PMCID: PMC4363162 DOI: 10.1111/nyas.12693] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/04/2014] [Accepted: 12/18/2014] [Indexed: 12/20/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some but not all carriers of small, noncoding CGG-repeat expansions (55-200 repeats; premutation) within the fragile X gene (FMR1). Principal features of FXTAS include intention tremor, cerebellar ataxia, Parkinsonism, memory and executive function deficits, autonomic dysfunction, brain atrophy with white matter disease, and cognitive decline. Although FXTAS was originally considered to be confined to the premutation range, rare individuals with a gray zone (45-54 repeats) or an unmethylated full mutation (>200 repeats) allele have now been described, the constant feature of the disorder remaining the requirement for FMR1 expression, in contradistinction to the gene silencing mechanism of fragile X syndrome. Although transcriptional activity is required for FXTAS pathogenesis, the specific trigger(s) for FXTAS pathogenesis remains elusive, highlighting the need for more research in this area. This need is underscored by recent neuroimaging findings of changes in the central nervous system that consistently appear well before the onset of clinical symptoms, thus creating an opportunity to delay or prevent the appearance of FXTAS.
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Affiliation(s)
- Paul J Hagerman
- Department of Biochemistry and Molecular Medicine, University of California , Davis , School of Medicine, Davis, California; The MIND Institute, University of California , Davis , Health System, Sacramento, California
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31
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Loesch DZ, Bui MQ, Hammersley E, Schneider A, Storey E, Stimpson P, Burgess T, Francis D, Slater H, Tassone F, Hagerman RJ, Hessl D. Psychological status in female carriers of premutation FMR1 allele showing a complex relationship with the size of CGG expansion. Clin Genet 2015; 87:173-178. [PMID: 24428240 DOI: 10.111/cage12347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/14/2014] [Accepted: 01/14/2014] [Indexed: 05/24/2023]
Abstract
We utilized a sample of 299 adult females aged between 19 and 86 years, carrying fragile X mental retardation (FMR1) alleles with small CCG expansions ranging from 50 to 141 repeats to analyse the relationships between psychological symptoms as assessed by the Symptom Checklist-90-Revised (SCL-90-R) and the size of the CGG repeat in the FMR1 gene. There were highly significant (negative) correlations between the size of the CGG repeat and a great majority of SCL-90-R subscale scores and all the global indices, suggesting that carriers of premutations in the mid-size CGG repeat range may be at greatest risk for the development of psychiatric disorder.
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Affiliation(s)
- D Z Loesch
- School of Psychological Science, La Trobe University, Bundoora, Victoria, Australia
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Jalnapurkar I, Rafika N, Tassone F, Hagerman R. Immune mediated disorders in women with a fragile X expansion and FXTAS. Am J Med Genet A 2014; 167A:190-7. [PMID: 25399540 DOI: 10.1002/ajmg.a.36748] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 08/06/2014] [Indexed: 12/17/2022]
Abstract
Premutation alleles in fragile X mental retardation 1 (FMR1) can cause the late-onset neurodegenerative disorder, fragile X-associated tremor ataxia syndrome (FXTAS) and/or the fragile X-associated primary ovarian insufficiency in approximately 20% of heterozygotes. Heterozygotes of the FMR1 premutation have a higher incidence of immune mediated disorders such as autoimmune thyroid disorder, especially when accompanied by FXTAS motor signs. We describe the time course of symptoms of immune mediated disorders and the subsequent development of FXTAS in four women with an FMR1 CGG expansion, including three with the premutation and one with a gray zone expansion. These patients developed an immune mediated disorder followed by neurological symptoms that become consistent with FXTAS. In all patients we observed a pattern involving an initial appearance of disease symptoms-often after a period of heightened stress (depression, anxiety, divorce, general surgery) followed by the onset of tremor and/or ataxia. Immune mediated diseases are associated with the manifestations of FXTAS temporally, although further studies are needed to clarify this association. If a cause and effect relationship can be established, treatment of pre-existing immune mediated disorders may benefit patients with pathogenic FMR1 mutations.
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Affiliation(s)
- Isha Jalnapurkar
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, Sacramento, California
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Muzar Z, Lozano R. Current research, diagnosis, and treatment of fragile X-associated tremor/ataxia syndrome. Intractable Rare Dis Res 2014; 3:101-9. [PMID: 25606360 PMCID: PMC4298640 DOI: 10.5582/irdr.2014.01029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/30/2014] [Indexed: 12/13/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is caused by a premutation CGG-repeat expansion in the 5'UTR of the fragile X mental retardation 1 (FMR1) gene. The classical clinical manifestations include tremor, cerebellar ataxia, cognitive decline and psychiatric disorders. Other less frequent features are peripheral neuropathy and autonomic dysfunction. Cognitive decline, a form of frontal subcortical dementia, memory loss and executive function deficits are also characteristics of this disorder. In this review, we present an expansion of recommendations for genetic testing for adults with suspected premutation disorders and provide an update of the clinical, radiological and molecular research of FXTAS, as well as the current research in the treatment for this intractable complex neurodegenerative genetic disorder.
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Affiliation(s)
- Zukhrofi Muzar
- UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
| | - Reymundo Lozano
- UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
- Address correspondence to: Dr. Reymundo Lozano, UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA. E-mail:
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Curinha A, Oliveira Braz S, Pereira-Castro I, Cruz A, Moreira A. Implications of polyadenylation in health and disease. Nucleus 2014; 5:508-19. [PMID: 25484187 DOI: 10.4161/nucl.36360] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Polyadenylation is the RNA processing step that completes the maturation of nearly all eukaryotic mRNAs. It is a two-step nuclear process that involves an endonucleolytic cleavage of the pre-mRNA at the 3'-end and the polymerization of a polyadenosine (polyA) tail, which is fundamental for mRNA stability, nuclear export and efficient translation during development. The core molecular machinery responsible for the definition of a polyA site includes several recognition, cleavage and polyadenylation factors that identify and act on a given polyA signal present in a pre-mRNA, usually an AAUAAA hexamer or similar sequence. This mechanism is tightly regulated by other cis-acting elements and trans-acting factors, and its misregulation can cause inefficient gene expression and may ultimately lead to disease. The majority of genes generate multiple mRNAs as a result of alternative polyadenylation in the 3'-untranslated region. The variable lengths of the 3' untranslated regions created by alternative polyadenylation are a recognizable target for differential regulation and clearly affect the fate of the transcript, ultimately modulating the expression of the gene. Over the past few years, several studies have highlighted the importance of polyadenylation and alternative polyadenylation in gene expression and their impact in a variety of physiological conditions, as well as in several illnesses. Abnormalities in the 3'-end processing mechanisms thus represent a common feature among many oncological, immunological, neurological and hematological disorders, but slight imbalances can lead to the natural establishment of a specific cellular state. This review addresses the key steps of polyadenylation and alternative polyadenylation in different cellular conditions and diseases focusing on the molecular effectors that ensure a faultless pre-mRNA 3' end formation.
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Key Words
- 3′ untranslated region
- 3′READS, 3′ Region Extraction and Deep Sequencing
- AD, Alzheimer disease
- APA, Alternative polyadenylation
- AREs, Au-rich elements
- BPV, bovine papilloma virus
- CAH, congenital adrenal hyperplasia
- CFIm25, Cleavage Factor Im 25 kDa
- COX-2, cyclooxygenase 2
- CPSF, Cleavage and Polyadenylation Specificity Factor
- CSTF2, cleavage stimulatory factor-64kDa
- DMKN, dermokine
- DSE, downstream sequence element
- ESC, embryonic stem cells
- FMR1, Fragil X mental retardation 1
- FOXP3, forkhead box P3
- FXPOI, fragile X-associated immature ovarian insufficiency
- FXS, Fragile X syndrome
- FXTAS, fragile X-associated tremor/ataxia syndrome
- HGRG-14, high-glucose-regulated gene
- IMP-1, Insulin-like growth factor 2 mRNA binding protein 1
- IPEX, immune dysfunction, polyendocrinopathy, enteropathy, X-linked
- LPS, lipopolysaccharide
- OPMD, oculopharyngeal muscular dystrophy
- PABPN1, poly(A) binding protein
- PAP, polyA polymerase
- PAS, polyA site
- PD, Parkinson disease
- PDXK, pyridoxal kinase
- PPIE, peptidylpropylisomerase E
- RBP, RNA-binding protein
- RNA Pol II, RNA polymerase II
- SLE, systemic lupus erythematosus
- SMA, Spinal Muscular Atrophy
- SMN, Survival Motor Neuron
- SNP, single nucleotide polymorphism
- StAR, steroigogenic acute regulatory
- TCF/LEF, T cell factor/lymphoid enhancer factor.
- TCF7L2, transcription factor 7-like 2
- TCR, T cell receptor
- TLI, tandem UTR length index
- TNF-α, tumor necrosis factor-α
- USE, upstream sequence element
- UTR, untranslated region
- WAS, Wiskott-Aldrich syndrome
- WASP, Wiskott-Aldrich syndrome protein
- aSyn, α-Synuclein
- aSynL, longest aSyn isoform
- alternative polyadenylation
- cell state
- disease
- gene expression
- miRNA, microRNA
- nuclear 1
- pA signal, polyA signal
- pA tail, polyA tail
- polyadenylation
- siRNAs, small interfering RNAs
- snRNPs, spliceosomal small nuclear ribonucleoproteins
- α-GalA, α-galactosidase A
- μ, IgM heavy-chain mRNA
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Affiliation(s)
- Ana Curinha
- a Gene Regulation Group; IBMC-Instituto de Biologia Molecular e Celular ; Universidade do Porto ; Porto , Portugal
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35
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Wheeler AC, Bailey DB, Berry-Kravis E, Greenberg J, Losh M, Mailick M, Milà M, Olichney JM, Rodriguez-Revenga L, Sherman S, Smith L, Summers S, Yang JC, Hagerman R. Associated features in females with an FMR1 premutation. J Neurodev Disord 2014; 6:30. [PMID: 25097672 PMCID: PMC4121434 DOI: 10.1186/1866-1955-6-30] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 03/19/2014] [Indexed: 12/31/2022] Open
Abstract
Changes in the fragile X mental retardation 1 gene (FMR1) have been associated with specific phenotypes, most specifically those of fragile X syndrome (FXS), fragile X tremor/ataxia syndrome (FXTAS), and fragile X primary ovarian insufficiency (FXPOI). Evidence of increased risk for additional medical, psychiatric, and cognitive features and conditions is now known to exist for individuals with a premutation, although some features have been more thoroughly studied than others. This review highlights the literature on medical, reproductive, cognitive, and psychiatric features, primarily in females, that have been suggested to be associated with changes in the FMR1 gene. Based on this review, each feature is evaluated with regard to the strength of evidence of association with the premutation. Areas of need for additional focused research and possible intervention strategies are suggested.
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Affiliation(s)
- Anne C Wheeler
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA ; Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Donald B Bailey
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA
| | | | - Jan Greenberg
- Waisman Center, University of Wisconsin, 1500 Highland Avenue, Madison, WI 53705, USA
| | - Molly Losh
- Northwestern University, 2240 Campus Drive, Evanston, IL 60208-3507, USA
| | - Marsha Mailick
- Waisman Center, University of Wisconsin, 1500 Highland Avenue, Madison, WI 53705, USA
| | - Montserrat Milà
- Biochemistry and Molecular Genetics Department, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain
| | - John M Olichney
- Center for Mind and Brain, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA ; MIND Institute, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA
| | - Laia Rodriguez-Revenga
- Biochemistry and Molecular Genetics Department, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain
| | | | - Leann Smith
- Waisman Center, University of Wisconsin, 1500 Highland Avenue, Madison, WI 53705, USA
| | - Scott Summers
- Center for Mind and Brain, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA ; MIND Institute, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA
| | - Jin-Chen Yang
- Center for Mind and Brain, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA ; MIND Institute, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA
| | - Randi Hagerman
- Center for Mind and Brain, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA ; MIND Institute, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA
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Birch RC, Cornish KM, Hocking DR, Trollor JN. Understanding the neuropsychiatric phenotype of fragile X-associated tremor ataxia syndrome: a systematic review. Neuropsychol Rev 2014; 24:491-513. [PMID: 24828430 DOI: 10.1007/s11065-014-9262-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/22/2014] [Indexed: 11/28/2022]
Abstract
Fragile X-associated tremor ataxia syndrome (FXTAS) is a recently identified X-linked neurodegenerative disorder affecting a proportion of premutation carriers of the Fragile X Mental Retardation 1 (FMR1) gene. Previous research suggests that cognitive and psychiatric features of FXTAS may include primary impairments in executive function and increased vulnerability to mood and anxiety disorders. A number of these reports, however, are based on overlapping cohorts or have produced inconsistent findings. A systematic review was therefore conducted to further elucidate the neuropsychiatric features characteristic of FXTAS. Fourteen papers met inclusion criteria for the review and were considered to represent nine independent FXTAS cohorts. Findings from the review suggest that the neuropsychiatric phenotype of FXTAS is characterised primarily by poorer performance on measures of executive function, working memory, information processing speed, and fine motor control when compared to matched comparison groups. Two studies were identified in which psychiatric symptoms in FXTAS were compared with controls, and these yielded mixed results. Overall the results of this review support previous reports that the neuropsychiatric profile of FXTAS is consistent with a dysexecutive fronto-subcortical syndrome. However, additional controlled studies are required to progress our understanding of FXTAS and how the neuropsychiatric profile relates to underlying pathological mechanisms.
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Affiliation(s)
- R C Birch
- Department of Developmental Disability Neuropsychiatry, School of Psychiatry, University of New South Wales, Sydney, Australia
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Schneider A, Ligsay A, Hagerman RJ. Fragile X syndrome: an aging perspective. ACTA ACUST UNITED AC 2014; 18:68-74. [PMID: 23949830 DOI: 10.1002/ddrr.1129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 04/24/2012] [Accepted: 06/19/2012] [Indexed: 11/11/2022]
Abstract
Cognitive and behavioral correlates of molecular variations related to the FMR1 gene have been studied rather extensively, but research about the long-term outcome in individuals with fragile X spectrum disorders remains sparse. In this review, we present an overview of aging research and recent findings in regard to cellular and clinical manifestations of aging in fragile X syndrome, and the FMR1 premutation.
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Affiliation(s)
- Andrea Schneider
- MIND Institute, University of California at Davis Medical Center, Sacramento, California, USA.
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Besterman AD, Wilke SA, Mulligan TE, Allison SC, Hagerman R, Seritan AL, Bourgeois JA. Towards an Understanding of Neuropsychiatric Manifestations in Fragile X Premutation Carriers. FUTURE NEUROLOGY 2014; 9:227-239. [PMID: 25013385 DOI: 10.2217/fnl.14.11] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fragile X-associated disorders (FXD) are a group of disorders caused by expansion of non-coding CGG repeat elements in the fragile X (FMR1) gene. One of these disorders, fragile X syndrome (FXS), is the most common heritable cause of intellectual disability, and is caused by large CGG repeat expansions (>200) resulting in silencing of the FMR1 gene. An increasingly recognized number of neuropsychiatric FXD have recently been identified that are caused by 'premutation' range expansions (55-200). These disorders are characterized by a spectrum of neuropsychiatric manifestations ranging from an increased risk of neurodevelopmental, mood and anxiety disorders to neurodegenerative phenotypes such as the fragile X-associated tremor ataxia syndrome (FXTAS). Here, we review advances in the clinical understanding of neuropsychiatric disorders in premutation carriers across the lifespan and offer guidance for the detection of such disorders by practicing psychiatrists and neurologists.
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Affiliation(s)
- Aaron D Besterman
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143 USA
| | - Scott A Wilke
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143 USA
| | - Tua-Elisabeth Mulligan
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143 USA
| | - Stephen C Allison
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143 USA
| | - Randi Hagerman
- Department of Pediatrics and MIND Institute, University of California Davis, Sacramento, California 95817 USA
| | - Andreea L Seritan
- Department of Psychiatry and Behavioral Sciences and MIND Institute, University of California Davis, Sacramento, California 95817 USA
| | - James A Bourgeois
- Department of Psychiatry, University of California San Francisco School of Medicine, San Francisco, California 94143 USA
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Leow A, Harvey D, Goodrich-Hunsaker NJ, Gadelkarim J, Kumar A, Zhan L, Rivera SM, Simon TJ. Altered structural brain connectome in young adult fragile X premutation carriers. Hum Brain Mapp 2014; 35:4518-30. [PMID: 24578183 DOI: 10.1002/hbm.22491] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/16/2014] [Accepted: 02/05/2014] [Indexed: 11/11/2022] Open
Abstract
Fragile X premutation carriers (fXPC) are characterized by 55-200 CGG trinucleotide repeats in the 5' untranslated region on the Xq27.3 site of the X chromosome. Clinically, they are associated with the fragile X-Associated Tremor/Ataxia Syndrome, a late-onset neurodegenerative disorder with diffuse white matter neuropathology. Here, we conducted first-ever graph theoretical network analyses in fXPCs using 30-direction diffusion-weighted magnetic resonance images acquired from 42 healthy controls aged 18-44 years (HC; 22 male and 20 female) and 46 fXPCs (16 male and 30 female). Globally, we found no differences between the fXPCs and HCs within each gender for all global graph theoretical measures. In male fXPCs, global efficiency was significantly negatively associated with the number of CGG repeats. For nodal measures, significant group differences were found between male fXPCs and male HCs in the right fusiform and the right ventral diencephalon (for nodal efficiency), and in the left hippocampus [for nodal clustering coefficient (CC)]. In female fXPCs, CC in the left superior parietal cortex correlated with counting performance in an enumeration task.
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Affiliation(s)
- Alex Leow
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois; Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, and Community Psychiatry, Sacramento, California
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Loesch DZ, Bui MQ, Hammersley E, Schneider A, Storey E, Stimpson P, Burgess T, Francis D, Slater H, Tassone F, Hagerman RJ, Hessl D. Psychological status in female carriers of premutation FMR1 allele showing a complex relationship with the size of CGG expansion. Clin Genet 2014; 87:173-8. [PMID: 24428240 DOI: 10.1111/cge.12347] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/14/2014] [Accepted: 01/14/2014] [Indexed: 11/26/2022]
Abstract
We utilized a sample of 299 adult females aged between 19 and 86 years, carrying fragile X mental retardation (FMR1) alleles with small CCG expansions ranging from 50 to 141 repeats to analyse the relationships between psychological symptoms as assessed by the Symptom Checklist-90-Revised (SCL-90-R) and the size of the CGG repeat in the FMR1 gene. There were highly significant (negative) correlations between the size of the CGG repeat and a great majority of SCL-90-R subscale scores and all the global indices, suggesting that carriers of premutations in the mid-size CGG repeat range may be at greatest risk for the development of psychiatric disorder.
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Affiliation(s)
- D Z Loesch
- School of Psychological Science, La Trobe University, Bundoora, Victoria, Australia
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Doll CA, Broadie K. Impaired activity-dependent neural circuit assembly and refinement in autism spectrum disorder genetic models. Front Cell Neurosci 2014; 8:30. [PMID: 24570656 PMCID: PMC3916725 DOI: 10.3389/fncel.2014.00030] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/21/2014] [Indexed: 01/23/2023] Open
Abstract
Early-use activity during circuit-specific critical periods refines brain circuitry by the coupled processes of eliminating inappropriate synapses and strengthening maintained synapses. We theorize these activity-dependent (A-D) developmental processes are specifically impaired in autism spectrum disorders (ASDs). ASD genetic models in both mouse and Drosophila have pioneered our insights into normal A-D neural circuit assembly and consolidation, and how these developmental mechanisms go awry in specific genetic conditions. The monogenic fragile X syndrome (FXS), a common cause of heritable ASD and intellectual disability, has been particularly well linked to defects in A-D critical period processes. The fragile X mental retardation protein (FMRP) is positively activity-regulated in expression and function, in turn regulates excitability and activity in a negative feedback loop, and appears to be required for the A-D remodeling of synaptic connectivity during early-use critical periods. The Drosophila FXS model has been shown to functionally conserve the roles of human FMRP in synaptogenesis, and has been centrally important in generating our current mechanistic understanding of the FXS disease state. Recent advances in Drosophila optogenetics, transgenic calcium reporters, highly-targeted transgenic drivers for individually-identified neurons, and a vastly improved connectome of the brain are now being combined to provide unparalleled opportunities to both manipulate and monitor A-D processes during critical period brain development in defined neural circuits. The field is now poised to exploit this new Drosophila transgenic toolbox for the systematic dissection of A-D mechanisms in normal versus ASD brain development, particularly utilizing the well-established Drosophila FXS disease model.
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Affiliation(s)
- Caleb A Doll
- Department of Biological Sciences, Vanderbilt University Nashville, TN, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University Nashville, TN, USA ; Kennedy Center for Research on Human Development, Vanderbilt University Nashville, TN, USA
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Polussa J, Schneider A, Hagerman R. Molecular Advances Leading to Treatment Implications for Fragile X Premutation Carriers. BRAIN DISORDERS & THERAPY 2014; 3:1000119. [PMID: 25436181 PMCID: PMC4245015 DOI: 10.4172/2168-975x.1000119] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fragile X syndrome (FXS) is the most common single gene cause of intellectual disability and it is characterized by a CGG expansion of more than 200 repeats in the FMR1 gene, leading to methylation of the promoter and gene silencing. The fragile X premutation, characterized by a 55 to 200 CGG repeat expansion, causes health problems and developmental difficulties in some, but not all, carriers. The premutation causes primary ovarian insufficiency in approximately 20% of females, psychiatric problems (including depression and/or anxiety) in approximately 50% of carriers and a neurodegenerative disorder, the fragile X-associated tremor ataxia syndrome (FXTAS), in approximately 40% of males and 16% of females later in life. Recent clinical studies in premutation carriers have expanded the health problems that may be seen. Advances in the molecular pathogenesis of the premutation have shown significant mitochondrial dysfunction and oxidative stress in neurons which may be amenable to treatment. Here we review the clinical problems of carriers and treatment recommendations.
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Affiliation(s)
- Jonathan Polussa
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health System, Sacramento, California, USA
- Department of Pediatrics, University of California Davis Health System, Sacramento, California, USA
| | - Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health System, Sacramento, California, USA
- Department of Pediatrics, University of California Davis Health System, Sacramento, California, USA
| | - Randi Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health System, Sacramento, California, USA
- Department of Pediatrics, University of California Davis Health System, Sacramento, California, USA
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Kim SY, Hashimoto RI, Tassone F, Simon TJ, Rivera SM. Altered neural activity of magnitude estimation processing in adults with the fragile X premutation. J Psychiatr Res 2013; 47:1909-16. [PMID: 24045061 PMCID: PMC3880247 DOI: 10.1016/j.jpsychires.2013.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/09/2013] [Accepted: 08/15/2013] [Indexed: 10/26/2022]
Abstract
Mutations of the fragile X mental retardation 1 (FMR1) gene are the genetic cause of fragile X syndrome (FXS). Expanded CGG trinucleotide repeat (>200 repeats) result in transcriptional silencing of the FMR1 gene and deficiency/absence of the FMR1 protein (FMRP). Carriers with a premutation allele (55-200 CGG repeats) are often associated with mildly reduced levels of FMRP and/or elevated levels of FMR1 mRNA, and are associated with the risk of developing a neurodegenerative disorder known as fragile X-associated tremor/ataxia syndrome (FXTAS). While impairments in numerical processing have been well documented in FXS, recent behavioral research suggests that premutation carriers also present with subtle but significant impairments in numerical processing. Using fMRI, the current study examined whether asymptomatic adults with the premutation would show aberrant neural correlates of magnitude estimation processing in the fronto-parietal area. Using a magnitude estimation task, we demonstrated that activity in the intraparietal sulcus and inferior frontal gyrus, associated with magnitude estimation processing, was significantly attenuated in premutation carriers compared to their neurotypical counterparts despite their comparable behavioral performance. Further, multiple regression analysis using CGG repeat size and FMR1 mRNA indicated that increased CGG repeat size is a primary factor for the decreased fronto-parietal activity, suggesting that reduced FMRP, rather than a toxic gain-of-function effect from elevated mRNA, contributes to altered neural activity of magnitude estimation processing in premutation carriers. In conclusion, we provide the first evidence on the aberrant neural correlates of magnitude estimation processing in premutation carriers accounted for by their FMR1 gene expression.
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Affiliation(s)
- So-Yeon Kim
- Center for Mind and Brain, University of California, Davis,Dept. of Psychiatry and Behavioral Sciences, University of California, Davis
| | | | | | - Tony J. Simon
- MIND Institute, University of California, Davis,Dept. of Psychiatry and Behavioral Sciences, University of California, Davis
| | - Susan M. Rivera
- Center for Mind and Brain, University of California, Davis,MIND Institute, University of California, Davis,Dept. of Psychology, University of California, Davis,Corresponding author: Susan M. Rivera, Ph.D, at Center for Mind and Brain, University of California, Davis, 267 Cousteau Place, Davis, CA 95618, USA., Tel.: +1 530 747 3802; Fax: +1 530 297 4603.,
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44
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Sørensen MJ, Grønborg TK, Christensen J, Parner ET, Vestergaard M, Schendel D, Pedersen LH. Antidepressant exposure in pregnancy and risk of autism spectrum disorders. Clin Epidemiol 2013; 5:449-59. [PMID: 24255601 PMCID: PMC3832387 DOI: 10.2147/clep.s53009] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Both the use of antidepressant medication during pregnancy and the prevalence of autism spectrum disorder have increased during recent years. A causal link has recently been suggested, but the association may be confounded by the underlying indication for antidepressant use. We investigated the association between maternal use of antidepressant medication in pregnancy and autism, controlling for potential confounding factors. Methods We identified all children born alive in Denmark 1996–2006 (n=668,468) and their parents in the Danish Civil Registration System. We obtained information on the mother’s prescriptions filled during pregnancy from the Danish National Prescription Registry, and on diagnoses of autism spectrum disorders in the children and diagnoses of psychiatric disorders in the parents from the Danish Psychiatric Central Register. In a cohort analysis, we estimated hazard ratios of autism spectrum disorders in children exposed to antidepressant medication during pregnancy compared with children who were not exposed, using Cox proportional hazards regression analysis. Furthermore, we estimated the risk for autism spectrum disorder in a sibling design. Results Children exposed prenatally to antidepressants had an adjusted hazard ratio of 1.5 (95% confidence interval [CI] 1.2–1.9) for autism spectrum disorder compared with unexposed children. Restricting the analysis to children of women with a diagnosis of affective disorder, the adjusted hazard ratio was 1.2 (95% CI 0.7–2.1), and the risk was further reduced when exposed children were compared with their unexposed siblings (adjusted hazard ratio 1.1; 95% CI 0.5–2.3). Conclusion After controlling for important confounding factors, there was no significant association between prenatal exposure to antidepressant medication and autism spectrum disorders in the offspring.
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Affiliation(s)
- Merete Juul Sørensen
- Regional Centre of Child and Adolescent Psychiatry, Aarhus University Hospital, Risskov, Denmark
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45
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Fernández E, Rajan N, Bagni C. The FMRP regulon: from targets to disease convergence. Front Neurosci 2013; 7:191. [PMID: 24167470 PMCID: PMC3807044 DOI: 10.3389/fnins.2013.00191] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 10/04/2013] [Indexed: 01/08/2023] Open
Abstract
The fragile X mental retardation protein (FMRP) is an RNA-binding protein that regulates mRNA metabolism. FMRP has been largely studied in the brain, where the absence of this protein leads to fragile X syndrome, the most frequent form of inherited intellectual disability. Since the identification of the FMRP gene in 1991, many studies have primarily focused on understanding the function/s of this protein. Hundreds of potential FMRP mRNA targets and several interacting proteins have been identified. Here, we report the identification of FMRP mRNA targets in the mammalian brain that support the key role of this protein during brain development and in regulating synaptic plasticity. We compared the genes from databases and genome-wide association studies with the brain FMRP transcriptome, and identified several FMRP mRNA targets associated with autism spectrum disorders, mood disorders and schizophrenia, showing a potential common pathway/s for these apparently different disorders.
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Affiliation(s)
- Esperanza Fernández
- Center for the Biology of Disease, Vlaams Institut voor Biotechnologie Leuven, Belgium ; Center for Human Genetics, Leuven Institute for Neuroscience and Disease, KU Leuven Leuven, Belgium
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46
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Santa María L, Pugin A, Alliende MA, Aliaga S, Curotto B, Aravena T, Tang HT, Mendoza-Morales G, Hagerman R, Tassone F. FXTAS in an unmethylated mosaic male with fragile X syndrome from Chile. Clin Genet 2013; 86:378-82. [PMID: 24028275 DOI: 10.1111/cge.12278] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/04/2013] [Accepted: 09/10/2013] [Indexed: 01/31/2023]
Abstract
Carriers of an FMR1 premutation allele (55-200 CGG repeats) often develop the neurodegenerative disorders, fragile X-associated tremor/ataxia syndrome (FXTAS). Neurological signs of FXTAS, parkinsonism and rapid onset of cognitive decline have not been reported in individuals with an unmethylated full mutation (FM). Here, we report a Chilean family affected with FXS, inherited from a parent carrier of an FMR1 unmethylated full mosaic allele, who presented with a fast progressing FXTAS. This case suggests that the definition of FXTAS may need to be broadened to not only include those with a premutation but also those with an expanded allele in FM range with a lack of methylation leading to elevated FMR1-mRNA expression levels and subsequent RNA toxicity.
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Affiliation(s)
- L Santa María
- Center for Diagnosis and Treatment of Fragile X Syndrome (CDTSXF), INTA University of Chile, Santiago, Chile
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47
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Li J, Huang W, Luo S, Lin Y, Duan R. Attitude of medical school students in China towards genetic testing and counseling issues in FXS. J Genet Couns 2013; 22:733-40. [PMID: 23955144 DOI: 10.1007/s10897-013-9634-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 07/25/2013] [Indexed: 12/01/2022]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. However, genetic testing protocols and genetic counseling guidelines for FXS are not yet established in mainland China. In the present study, we conducted a comprehensive analysis using a self-administered questionnaire among students at the Xiangya medical school to investigate their attitude towards genetic testing and counseling issues of FXS. We have gained a general understanding of the attitudes of medical students towards these FXS issues in China. This information is of immense importance to develop appropriate genetic tests and to train counselors for FXS. As the medical school students surveyed are prospective physicians who will be a part of the Chinese health system, our survey was focused on the basic knowledge of FXS, population-based FXS screening, confidentiality and reproductive options for mutation carriers. The study demonstrated that only less than one third of the participants had heard about FXS. 94.6 % of participants were in favor of FXS screening for women in their reproductive age who had a genetic history of FXS. Furthermore, only half of the participants would inform their families about their genetic status in case of positive test results, and more than half of the participants supported natural conception and prenatal diagnosis for FXS mutation carriers. Additional findings and research implications are also discussed. This survey targeting potential doctors provides important information for the development of FXS genetic test and counselor training for the Chinese health system.
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Affiliation(s)
- Jia Li
- State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, 410078, China
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48
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Tassone F, Choudhary NS, Tassone F, Durbin-Johnson B, Hansen R, Hertz-Picciotto I, Pessah I. Identification of expanded alleles of the FMR1 Gene in the CHildhood Autism Risks from Genes and Environment (CHARGE) study. J Autism Dev Disord 2013; 43:530-9. [PMID: 22767137 DOI: 10.1007/s10803-012-1580-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fragile X syndrome (FXS) is a neuro-developmental disorder characterized by intellectual disabilities and autism spectrum disorders (ASD). Expansion of a CGG trinucleotide repeat (>200 repeats) in the 5'UTR of the fragile X mental retardation gene, is the single most prevalent cause of cognitive disabilities. Several screening studies for FXS, among individuals with ID from different ethnic populations, have indicated that the prevalence of the syndrome varies between 0.5 and 16 %. Because the high co-morbidity with autism, we have conducted a screening study of the cohort from CHARGE, a large-scale, population-based, case control study. We have identified six subjects carrying an expanded allele, which emphasize the importance of screening for FXS in a population with intellectual disabilities and ASD.
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Affiliation(s)
- Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, 2700 Stockton Blvd, Suite 2102, Sacramento, CA 95817, USA.
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Schneider A, Seritan A, Tassone F, Rivera SM, Hagerman R, Hessl D. Psychiatric features in high-functioning adult brothers with fragile x spectrum disorders. Prim Care Companion CNS Disord 2013; 15:12l01492. [PMID: 23930232 DOI: 10.4088/pcc.12l01492] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
- Andrea Schneider
- MIND Medical Investigation of Neurodevelopmental Disorders Institute (Drs Schneider, Tassone, Hagerman, and Hessl) and Departments of Psychiatry and Behavioral Sciences (Drs Seritan and Hessl), Biochemistry (Dr Tassone), Psychology (Dr Rivera), and Pediatrics (Drs Schneider and Hagerman), University of California-Davis Medical Center, Sacramento
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50
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Fragile X-associated tremor/ataxia syndrome (FXTAS): pathology and mechanisms. Acta Neuropathol 2013; 126:1-19. [PMID: 23793382 DOI: 10.1007/s00401-013-1138-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/30/2013] [Indexed: 12/17/2022]
Abstract
Since its discovery in 2001, our understanding of fragile X-associated tremor/ataxia syndrome (FXTAS) has undergone a remarkable transformation. Initially characterized rather narrowly as an adult-onset movement disorder, the definition of FXTAS is broadening; moreover, the disorder is now recognized as only one facet of a much broader clinical pleiotropy among children and adults who carry premutation alleles of the FMR1 gene. Furthermore, the intranuclear inclusions of FXTAS, once thought to be a CNS-specific marker of the disorder, are now known to be widely distributed in multiple non-CNS tissues; this observation fundamentally changes our concept of the disease, and may provide the basis for understanding the diverse medical problems associated with the premutation. Recent work on the pathogenic mechanisms underlying FXTAS indicates that the origins of the late-onset neurodegenerative disorder actually lie in early development, raising the likelihood that all forms of clinical involvement among premutation carriers have a common underlying mechanistic basis. There has also been great progress in our understanding of the triggering event(s) in FXTAS pathogenesis, which is now thought to involve sequestration of one or more nuclear proteins involved with microRNA biogenesis. Moreover, there is mounting evidence that mitochondrial dysregulation contributes to the decreased cell function and loss of viability, evident in mice even during the neonatal period. Taken together, these recent findings offer hope for early interventions for FXTAS, well before the onset of overt disease, and for the treatment of other forms of clinical involvement among premutation carriers.
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