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Zucker A, Hinton VJ. Autistic Traits Associated with the Fragile X Premutation Allele: The Neurodevelopmental Profile. Dev Neuropsychol 2024; 49:153-166. [PMID: 38753030 DOI: 10.1080/87565641.2024.2351795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 04/29/2024] [Indexed: 05/22/2024]
Abstract
Although most individuals who carry the Fragile X premutation allele, defined as 55-200 CGG repeats on the X-linked FMR1 gene (Fragile X Messenger Ribonucleoprotein 1 gene), do not meet diagnostic criteria for autism spectrum disorder, there is a suggestion of increased behaviors associated with subtle autistic traits. More autism associated characteristics have been reported among adults than children. This may highlight a possible worsening developmental trajectory, variable findings due to research quality or differences in number of studies done in adults vs children, rather than true developmental changes. This review is designed to examine the neurodevelopmental profile associated with the premutation allele from a developmental perspective, focused on autistic traits.
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Affiliation(s)
- Ariel Zucker
- The Graduate Center, City University of New York, New York, USA
- Queens College, City University of New York, New York, USA
| | - Veronica J Hinton
- The Graduate Center, City University of New York, New York, USA
- Queens College, City University of New York, New York, USA
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2
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Kargar M, Hagerman RJ, Martínez-Cerdeño V. Neurodegeneration of White and Gray Matter in the Hippocampus with FXTAS. Int J Mol Sci 2023; 24:17266. [PMID: 38139097 PMCID: PMC10743470 DOI: 10.3390/ijms242417266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/07/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder that affects older premutation carriers (55-200 CGG repeats) of the fragile X gene. Despite the high prevalence of the FXTAS disorder, neuropathology studies of individuals affected by FXTAS are limited. We performed hematoxylin and eosin (H&E) staining in the hippocampus of 26 FXTAS cases and analyzed the tissue microscopically. The major neuropathological characteristics were white matter disease, intranuclear inclusions in neurons and astrocytes, and neuron loss. Astrocytes contained more and larger inclusions than neurons. There was a negative correlation between age of death and CGG repeat length in cases over the age of 60. The number of astroglial inclusions (CA3 and dentate gyrus) and the number of CA3 neuronal inclusions increased with elevated CGG repeat length. In the two cases with a CGG repeat size less than 65, FXTAS intranuclear inclusions were not present in the hippocampus, while in the two cases with less than 70 (65-70) CGG repeat expansion, neurons and astrocytes with inclusions were occasionally identified in the CA1 sub-region. These findings add hippocampus neuropathology to the previously reported changes in other areas of the brain in FXTAS patients, with implications for understanding FXTAS pathogenesis.
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Affiliation(s)
- Maryam Kargar
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, USA
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA
| | - Randi J. Hagerman
- MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA;
| | - Verónica Martínez-Cerdeño
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, USA
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA
- MIND Institute, UC Davis School of Medicine, Sacramento, CA 95817, USA;
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3
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Wang JY, Grigsby J, Placido D, Wei H, Tassone F, Kim K, Hessl D, Rivera SM, Hagerman RJ. Clinical and Molecular Correlates of Abnormal Changes in the Cerebellum and Globus Pallidus in Fragile X Premutation. Front Neurol 2022; 13:797649. [PMID: 35211082 PMCID: PMC8863211 DOI: 10.3389/fneur.2022.797649] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 01/12/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Fragile X premutation carriers (55-200 CGG triplets) may develop a progressive neurodegenerative disorder, fragile X-associated tremor/ataxia syndrome (FXTAS), after the age of 50. The neuroradiologic markers of FXTAS are hyperintense T2-signals in the middle cerebellar peduncle-the MCP sign. We recently noticed abnormal T2-signals in the globus pallidus in male premutation carriers and controls but the prevalence and clinical significance were unknown. METHODS We estimated the prevalence of the MCP sign and pallidal T2-abnormalities in 230 male premutation carriers and 144 controls (aged 8-86), and examined the associations with FXTAS symptoms, CGG repeat length, and iron content in the cerebellar dentate nucleus and globus pallidus. RESULTS Among participants aged ≥45 years (175 premutation carriers and 82 controls), MCP sign was observed only in premutation carriers (52 vs. 0%) whereas the prevalence of pallidal T2-abnormalities approached significance in premutation carriers compared with controls after age-adjustment (25.1 vs. 13.4%, p = 0.069). MCP sign was associated with impaired motor and executive functioning, and the additional presence of pallidal T2-abnormalities was associated with greater impaired executive functioning. Among premutation carriers, significant iron accumulation was observed in the dentate nucleus, and neither pallidal or MCP T2-abnormalities affected measures of the dentate nucleus. While the MCP sign was associated with CGG repeat length >75 and dentate nucleus volume correlated negatively with CGG repeat length, pallidal T2-abnormalities did not correlate with CGG repeat length. However, pallidal signal changes were associated with age-related accelerated iron depletion and variability and having both MCP and pallidal signs further increased iron variability in the globus pallidus. CONCLUSIONS Only the MCP sign, not pallidal abnormalities, revealed independent associations with motor and cognitive impairment; however, the occurrence of combined MCP and pallidal T2-abnormalities may present a risk for greater cognitive impairment and increased iron variability in the globus pallidus.
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Affiliation(s)
- Jun Yi Wang
- Center for Mind and Brain, University of California, Davis, Davis, CA, United States
| | - Jim Grigsby
- Departments of Psychology and Medicine, University of Colorado Denver, Denver, CO, United States
| | - Diego Placido
- Department of Psychology, University of California, Davis, Davis, CA, United States
| | - Hongjiang Wei
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute for Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA, United States
- The MIND Institute, University of California Davis Medical Center, Sacramento, CA, United States
| | - Kyoungmi Kim
- Department of Public Health Sciences, University of California Davis School of Medicine, Sacramento, CA, United States
| | - David Hessl
- The MIND Institute, University of California Davis Medical Center, Sacramento, CA, United States
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, United States
| | - Susan M. Rivera
- Center for Mind and Brain, University of California, Davis, Davis, CA, United States
- Departments of Psychology and Medicine, University of Colorado Denver, Denver, CO, United States
- The MIND Institute, University of California Davis Medical Center, Sacramento, CA, United States
| | - Randi J. Hagerman
- The MIND Institute, University of California Davis Medical Center, Sacramento, CA, United States
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, United States
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4
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Elias-Mas A, Alvarez-Mora MI, Caro-Benito C, Rodriguez-Revenga L. Neuroimaging Insight Into Fragile X-Associated Neuropsychiatric Disorders: Literature Review. Front Psychiatry 2021; 12:728952. [PMID: 34721105 PMCID: PMC8554234 DOI: 10.3389/fpsyt.2021.728952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/17/2021] [Indexed: 11/29/2022] Open
Abstract
FMR1 premutation is defined by 55-200 CGG repeats in the Fragile X Mental Retardation 1 (FMR1) gene. FMR1 premutation carriers are at risk of developing a neurodegenerative disease called fragile X-associated tremor/ataxia syndrome (FXTAS) and Fragile X-associated primary ovarian insufficiency (FXPOI) in adulthood. In the last years an increasingly board spectrum of clinical manifestations including psychiatric disorders have been described as occurring at a greater frequency among FMR1 premutation carriers. Herein, we reviewed the neuroimaging findings reported in relation with psychiatric symptomatology in adult FMR1 premutation carriers. A structured electronic literature search was conducted on FMR1 premutation and neuroimaging yielding a total of 3,229 articles examined. Of these, 7 articles were analyzed and are included in this review. The results showed that the main radiological findings among adult FMR1 premutation carriers presenting neuropsychiatric disorders were found on the amygdala and hippocampus, being the functional abnormalities more consistent and the volumetric changes more inconsistent among studies. From a molecular perspective, CGG repeat size, FMR1 mRNA and FMRP levels have been investigated in relation with the neuroimaging findings. Based on the published results, FMRP might play a key role in the pathophysiology of the psychiatric symptoms described among FMR1 premutation carriers. However, additional studies including further probes of brain function and a broader scope of psychiatric symptom measurement are required in order to obtain a comprehensive landscape of the neuropsychiatric phenotype associated with the FMR1 premutation.
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Affiliation(s)
- Andrea Elias-Mas
- Radiology Department, Hospital Universitari Mútua de Terrassa, Terrassa, Spain.,Institute for Research and Innovation Parc Taulí (I3PT), Sabadell, Spain.,Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Maria Isabel Alvarez-Mora
- Biochemistry and Molecular Genetics Department, Hospital Clinic of Barcelona, Barcelona, Spain.,CIBER of Rare Diseases (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Laia Rodriguez-Revenga
- Biochemistry and Molecular Genetics Department, Hospital Clinic of Barcelona, Barcelona, Spain.,CIBER of Rare Diseases (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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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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6
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Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS): Pathophysiology and Clinical Implications. Int J Mol Sci 2020; 21:ijms21124391. [PMID: 32575683 PMCID: PMC7352421 DOI: 10.3390/ijms21124391] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 02/06/2023] Open
Abstract
The fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder seen in older premutation (55-200 CGG repeats) carriers of FMR1. The premutation has excessive levels of FMR1 mRNA that lead to toxicity and mitochondrial dysfunction. The clinical features usually begin in the 60 s with an action or intention tremor followed by cerebellar ataxia, although 20% have only ataxia. MRI features include brain atrophy and white matter disease, especially in the middle cerebellar peduncles, periventricular areas, and splenium of the corpus callosum. Neurocognitive problems include memory and executive function deficits, although 50% of males can develop dementia. Females can be less affected by FXTAS because of a second X chromosome that does not carry the premutation. Approximately 40% of males and 16% of female carriers develop FXTAS. Since the premutation can occur in less than 1 in 200 women and 1 in 400 men, the FXTAS diagnosis should be considered in patients that present with tremor, ataxia, parkinsonian symptoms, neuropathy, and psychiatric problems. If a family history of a fragile X mutation is known, then FMR1 DNA testing is essential in patients with these symptoms.
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7
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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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8
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Napoli E, Schneider A, Wang JY, Trivedi A, Carrillo NR, Tassone F, Rogawski M, Hagerman RJ, Giulivi C. Allopregnanolone Treatment Improves Plasma Metabolomic Profile Associated with GABA Metabolism in Fragile X-Associated Tremor/Ataxia Syndrome: a Pilot Study. Mol Neurobiol 2019; 56:3702-3713. [PMID: 30187385 PMCID: PMC6401336 DOI: 10.1007/s12035-018-1330-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/22/2018] [Indexed: 12/17/2022]
Abstract
Currently, there is no effective treatment for the fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder. In this pilot study, we evaluated whether allopregnanolone, a natural neurosteroid that exerts beneficial effects in neurodegenerative diseases, nervous system injury, and peripheral neuropathies, could improve lymphocytic bioenergetics and plasma pharmacometabolomics in six males with FXTAS (68 ± 3 years old; FMR1 CGG repeats 94 ± 4; FXTAS stages ranging from 3 to 5) enrolled in a 12-week open-label intervention study conducted at the University of California Davis from December 2015 through July 2016. Plasma pharmacometabolomics and lymphocytic mitochondria function were assessed at baseline (on the day of the first infusion) and at follow-up (within 48 h from the last infusion). In parallel, quantitative measurements of tremor and ataxia and neuropsychological evaluations of mental state, executive function, learning, memory, and psychological symptoms were assessed at the same time points. Allopregnanolone treatment impacted significantly GABA metabolism, oxidative stress, and some of the mitochondria-related outcomes. Notably, the magnitude of the individual metabolic response, as well as the correlation with some of the behavioral tests, was overwhelmingly carrier-specific. Based on this pilot study, allopregnanolone treatment has the potential for improving cognitive and GABA metabolism in FXTAS aligned with the concept of precision medicine.
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Affiliation(s)
- Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA
| | - Andrea Schneider
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA, USA
- UC Davis Health, UC Davis MIND Institute, Sacramento, CA, USA
| | - Jun Yi Wang
- UC Davis Health, UC Davis MIND Institute, Sacramento, CA, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Aditi Trivedi
- School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Nika Roa Carrillo
- School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Flora Tassone
- UC Davis Health, UC Davis MIND Institute, Sacramento, CA, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Michael Rogawski
- Department of Neurology, School of Medicine, University of California Davis, Sacramento, CA, USA
| | - Randi J Hagerman
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA, USA
- UC Davis Health, UC Davis MIND Institute, Sacramento, CA, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA.
- UC Davis Health, UC Davis MIND Institute, Sacramento, CA, USA.
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9
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Abstract
The FMR1 premutation confers a 40–60% risk for males of developing a neurodegenerative disease called the Fragile X-associated Tremor Ataxia Syndrome (FXTAS). FXTAS is a late-onset disease that primarily involves progressive symptoms of tremor and ataxia, as well as cognitive decline that can develop into dementia in some patients. At present, it is not clear whether changes to brain function are detectable in motor regions prior to the onset of frank symptomatology. The present study therefore aimed to utilize an fMRI motor task for the first time in an asymptomatic premutation population. Premutation carriers without a diagnosis of FXTAS (n = 17) and a group of healthy male controls (n = 17), with an age range of 24–68 years old, were recruited for this cross-sectional study. This study utilized neuroimaging, molecular and clinical measurements, employing an fMRI finger-tapping task with a block design consisting of sequential finger-tapping, random finger-tapping and rest conditions. The imaging analysis contrasted the sequential and random conditions to investigate activation changes in response to a change in task demand. Additionally, measurements were obtained of participant tremor, co-ordination and balance using the CATSYS-2000 system and measures of FMR1 mRNA were quantified from peripheral blood samples using quantitative real-time PCR methodology. Premutation carriers demonstrated significantly less cerebellar activation than controls during sequential versus random finger tapping (FWEcorr < 0.001). In addition, there was a significant age by group interaction in the hippocampus, inferior parietal cortex and temporal cortex originating from a more negative relationship between brain activation and age in the carrier group compared to the controls (FWEcorr < 0.001). Here, we present for the first time functional imaging-based evidence for early movement-related neurodegeneration in Fragile X premutation carriers. These changes pre-exist the diagnosis of FXTAS and are greatest in older carriers suggesting that they may be indicative of FXTAS vulnerability. The authors present a cross-sectional fMRI study in male carriers of the FMR1 premutation Carriers show decreased BOLD activation at the cerebellum in response to change in task demand in a finger-tapping task Carriers exhibit a group x age interaction of BOLD response in the temporoparietal area These changes pre-exist the diagnosis of the Fragile X-associated Tremor/Ataxia Syndrome (FXTAS)
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10
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Wang JY, Trivedi AM, Carrillo NR, Yang J, Schneider A, Giulivi C, Adams P, Tassone F, Kim K, Rivera SM, Lubarr N, Wu CY, Irwin RW, Brinton RD, Olichney JM, Rogawski MA, Hagerman RJ. Open-Label Allopregnanolone Treatment of Men with Fragile X-Associated Tremor/Ataxia Syndrome. Neurotherapeutics 2017; 14:1073-1083. [PMID: 28707277 PMCID: PMC5722761 DOI: 10.1007/s13311-017-0555-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder affecting approximately 45% of male and 16% of female carriers of the FMR1 premutation over the age of 50 years. Currently, no effective treatment is available. We performed an open-label intervention study to assess whether allopregnanolone, a neurosteroid promoting regeneration and repair, can improve clinical symptoms, brain activity, and magnetic resonance imaging (MRI) measurements in patients with FXTAS. Six patients underwent weekly intravenous infusions of allopregnanolone (2-6 mg over 30 min) for 12 weeks. All patients completed baseline and follow-up studies, though MRI scans were not collected from 1 patient because of MRI contraindications. The MRI scans from previous visits, along with scans from 8 age-matched male controls, were also included to establish patients' baseline condition as a reference. Functional outcomes included quantitative measurements of tremor and ataxia and neuropsychological evaluations. Brain activity consisted of event-related potential N400 word repetition effect during a semantic memory processing task. Structural MRI outcomes comprised volumes of the hippocampus, amygdala, and fluid-attenuated inversion recovery hyperintensities, and microstructural integrity of the corpus callosum. The results of the study showed that allopregnanolone infusions were well tolerated in all subjects. Before treatment, the patients disclosed impairment in executive function, verbal fluency and learning, and progressive deterioration of all MRI measurements. After treatment, the patients demonstrated improvement in executive functioning, episodic memory and learning, and increased N400 repetition effect amplitude. Although MRI changes were not significant as a group, both improved and deteriorated MRI measurements occurred in individual patients in contrast to uniform deterioration before the treatment. Significant correlations between baseline MRI measurements and changes in neuropsychological test scores indicated the effects of allopregnanolone on improving executive function, learning, and memory for patients with relatively preserved hippocampus and corpus callosum, while reducing psychological symptoms for patients with small hippocampi and amygdalae. The findings show the promise of allopregnanolone in improving cognitive functioning in patients with FXTAS and in partially alleviating some aspects of neurodegeneration. Further studies are needed to verify the efficacy of allopregnanolone for treating FXTAS.
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Affiliation(s)
- J Y Wang
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - A M Trivedi
- School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - N R Carrillo
- School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - J Yang
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, USA
- Center for Mind and Brain, University of California, Davis, Davis, CA, USA
| | - A Schneider
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Department of Pediatrics, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - C Giulivi
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Department of Molecular Biosciences, University of California Davis, School of Veterinary Medicine, Davis, CA, USA
| | - P Adams
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Department of Pediatrics, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - F Tassone
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - K Kim
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Department of Public Health Sciences, University of California, Davis, Davis, CA, USA
| | - S M Rivera
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA
- Center for Mind and Brain, University of California, Davis, Davis, CA, USA
- Department of Psychology, University of California Davis, Davis, CA, USA
| | - N Lubarr
- Department of Neurology, Mount Sinai Beth Israel Hospital, New York, NY, USA
| | - C-Y Wu
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, USA
- PK/PD Bioanalytical Core Facility, UC Davis Health, Sacramento, CA, USA
| | - R W Irwin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - R D Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
- Center for Innovation in Brain Science, School of Medicine, Departments of Pharmacology and Neurology, University of Arizona, Tucson, AZ, USA
| | - J M Olichney
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, USA
- Center for Mind and Brain, University of California, Davis, Davis, CA, USA
| | - M A Rogawski
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, USA
- Department of Pharmacology, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - R J Hagerman
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, USA.
- Department of Pediatrics, School of Medicine, University of California, Davis, Sacramento, CA, USA.
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11
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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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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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13
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Klusek J, LaFauci G, Adayev T, Brown WT, Tassone F, Roberts JE. Reduced vagal tone in women with the FMR1 premutation is associated with FMR1 mRNA but not depression or anxiety. J Neurodev Disord 2017; 9:16. [PMID: 28469730 PMCID: PMC5414146 DOI: 10.1186/s11689-017-9197-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 04/21/2017] [Indexed: 12/12/2022] Open
Abstract
Background Autonomic dysfunction is implicated in a range of psychological conditions, including depression and anxiety. The fragile X mental retardation-1 (FMR1) premutation is a common genetic mutation that affects ~1:150 women and is associated with psychological vulnerability. This study examined cardiac indicators of autonomic function among women with the FMR1 premutation and control women as potential biomarkers for psychological risk that may be linked to FMR1. Methods Baseline inter-beat interval and respiratory sinus arrhythmia (a measure of parasympathetic vagal tone) were measured in 35 women with the FMR1 premutation and 28 controls. The women completed anxiety and depression questionnaires. FMR1 genetic indices (i.e., CGG repeat, quantitative FMRP, FMR1 mRNA, activation ratio) were obtained for the premutation group. Results Respiratory sinus arrhythmia was reduced in the FMR1 premutation group relative to controls. While depression symptoms were associated with reduced respiratory sinus arrhythmia among control women, these variables were unrelated in the FMR1 premutation. Elevated FMR1 mRNA was associated with higher respiratory sinus arrhythmia. Conclusions Women with the FMR1 premutation demonstrated autonomic dysregulation characterized by reduced vagal tone. Unlike patterns observed in the general population and in study controls, vagal activity and depression symptoms were decoupled in women with the FMR1 premutation, suggesting independence between autonomic regulation and psychopathological symptoms that is atypical and potentially specific to the FMR1 premutation. The association between vagal tone and mRNA suggests that molecular variation associated with FMR1 plays a role in autonomic regulation.
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Affiliation(s)
- Jessica Klusek
- Department of Communication Sciences and Disorders, University of South Carolina, Keenan Building, Suite 300, Columbia, SC 29208 USA
| | - Giuseppe LaFauci
- Department of Developmental Biochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314 USA
| | - Tatyana Adayev
- Department of Developmental Biochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314 USA
| | - W Ted Brown
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314 USA
| | - Flora Tassone
- UC Davis MIND Institute, University of California Davis, 2825 50th Street, Sacramento, CA 95817 USA
| | - Jane E Roberts
- Department of Psychology, University of South Carolina, 1512 Pendleton Street, Columbia, SC 29208 USA
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14
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Gossett A, Sansone S, Schneider A, Johnston C, Hagerman R, Tassone F, Rivera SM, Seritan AL, Hessl D. Psychiatric disorders among women with the fragile X premutation without children affected by fragile X syndrome. Am J Med Genet B Neuropsychiatr Genet 2016; 171:1139-1147. [PMID: 27615674 PMCID: PMC6907071 DOI: 10.1002/ajmg.b.32496] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/19/2016] [Indexed: 11/07/2022]
Abstract
Several studies have demonstrated increased rates of anxiety and depressive disorders among female carriers of the fragile X premutation. However, the majority of these studies focused on mothers of children with fragile X syndrome, who experience higher rates of parenting stress that may contribute to the emergence of these disorders. The present study compared psychiatric symptom presentation (utilizing measures of current symptoms and lifetime DSM-IV Axis I disorders) in 24 female carriers without affected children (mean age = 32.1 years) to 26 non-carrier women from the community (mean age = 30.5 years). We also examined the association between CGG repeat size (adjusted for X activation ratio) and mRNA, with severity of psychiatric symptoms. Women with the premutation reported significantly elevated symptoms of anxiety, depression, interpersonal sensitivity, obsessive-compulsiveness, and somatization relative to controls during the past week. Carriers had significantly higher rates of lifetime social phobia (42.3%) compared to controls (12.5%); however, this comparison did not remain significant after multiple comparison adjustment. Rates of other psychiatric disorders were not significantly elevated relative to controls, though it should be noted that lifetime rates among controls were much higher than previously published population estimates. Although the sample is relatively small, the study of this unique cohort suggests the premutation confers risk for mood and anxiety disorders independent of the stress of parenting children with FXS. Screening for psychiatric disorders in women with the premutation, even before they become parents, is important and highly encouraged. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Amy Gossett
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Psychology, California School of Professional Psychology, Alliant International University, Sacramento, California
| | - Stephanie Sansone
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, California
| | - Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, California
| | - Cindy Johnston
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, California
| | - Randi Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, California
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, California
| | - Susan M. Rivera
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Psychology, University of California Davis, Davis, California
- Center for Mind and Brain, University of California Davis, Davis, California
| | - Andreea L. Seritan
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, California
| | - David Hessl
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, Sacramento, California
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, California
- Correspondence to: David Hessl, Ph.D., Department of Psychiatry and Behavioral Sciences, MIND Institute, UC Davis, 2825 50th St., Sacramento, CA 95817.
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15
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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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16
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Robertson EE, Hall DA, McAsey AR, O'Keefe JA. Fragile X-associated tremor/ataxia syndrome: phenotypic comparisons with other movement disorders. Clin Neuropsychol 2016; 30:849-900. [PMID: 27414076 PMCID: PMC7336900 DOI: 10.1080/13854046.2016.1202239] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 06/12/2016] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The purpose of this paper is to review the typical cognitive and motor impairments seen in fragile X-associated tremor/ataxia syndrome (FXTAS), essential tremor (ET), Parkinson disease (PD), spinocerebellar ataxias (SCAs), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP) in order to enhance diagnosis of FXTAS patients. METHODS We compared the cognitive and motor phenotypes of FXTAS with each of these other movement disorders. Relevant neuropathological and neuroimaging findings are also reviewed. Finally, we describe the differences in age of onset, disease severity, progression rates, and average lifespan in FXTAS compared to ET, PD, SCAs, MSA, and PSP. We conclude with a flow chart algorithm to guide the clinician in the differential diagnosis of FXTAS. RESULTS By comparing the cognitive and motor phenotypes of FXTAS with the phenotypes of ET, PD, SCAs, MSA, and PSP we have clarified potential symptom overlap while elucidating factors that make these disorders unique from one another. In summary, the clinician should consider a FXTAS diagnosis and testing for the Fragile X mental retardation 1 (FMR1) gene premutation if a patient over the age of 50 (1) presents with cerebellar ataxia and/or intention tremor with mild parkinsonism, (2) has the middle cerebellar peduncle (MCP) sign, global cerebellar and cerebral atrophy, and/or subcortical white matter lesions on MRI, or (3) has a family history of fragile X related disorders, intellectual disability, autism, premature ovarian failure and has neurological signs consistent with FXTAS. Peripheral neuropathy, executive function deficits, anxiety, or depression are supportive of the diagnosis. CONCLUSIONS Distinct profiles in the cognitive and motor domains between these movement disorders may guide practitioners in the differential diagnosis process and ultimately lead to better medical management of FXTAS patients.
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Affiliation(s)
- Erin E Robertson
- a Department of Anatomy and Cell Biology , Rush University , Chicago , IL , USA
| | - Deborah A Hall
- b Department of Neurological Sciences , Rush University , Chicago , IL , USA
| | - Andrew R McAsey
- a Department of Anatomy and Cell Biology , Rush University , Chicago , IL , USA
| | - Joan A O'Keefe
- a Department of Anatomy and Cell Biology , Rush University , Chicago , IL , USA
- b Department of Neurological Sciences , Rush University , Chicago , IL , USA
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17
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Yang JC, Simon C, Niu YQ, Bogost M, Schneider A, Tassone F, Seritan A, Grigsby J, Hagerman PJ, Hagerman RJ, Olichney JM. Phenotypes of hypofrontality in older female fragile X premutation carriers. Ann Neurol 2014; 74:275-83. [PMID: 23686745 DOI: 10.1002/ana.23933] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 03/28/2013] [Accepted: 04/26/2013] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To investigate the nature of cognitive impairments and underlying brain mechanisms in older female fragile X premutation carriers with and without fragile X-associated tremor/ataxia syndrome (FXTAS). METHODS Extensive neuropsychological testing and cognitive event-related brain potentials (ERPs; particularly, the auditory P300) were examined in 84 female participants: 33 fragile X premutation carriers with FXTAS (mean age = 62.8 years), 25 premutation carriers without FXTAS (mean age = 55.4 years), and 26 normal healthy controls (mean age = 59.3 years). RESULTS Both premutation groups exhibited executive dysfunction on the Behavioral Dyscontrol Scale, with subtle impairments in inhibition and performance monitoring in female carriers without FXTAS, and more substantial deficits in FXTAS women. However, the female carrier group without FXTAS showed more pronounced deficiencies in working memory. Abnormal ERPs were recorded over the frontal lobes, where FXTAS patients showed both P300 amplitude reduction and latency prolongation, whereas only decreased frontal P300 amplitudes were found in carriers without FXTAS. These frontal P300 measures correlated with executive function and information processing speed. INTERPRETATION The neuropsychological testing and ERP results of the present study provide support for the hypothesis that executive dysfunction is the primary cognitive impairment among older female premutation carriers both with and without FXTAS, although these deficits are relatively mild compared to those in FXTAS males. These findings are consistent with a synergistic effect of the premutation and aging on cognitive impairment among older female fragile X premutation carriers, even in those without FXTAS symptoms.
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Affiliation(s)
- Jin-Chen Yang
- Center for Mind and Brain, University of California, Davis, Davis, CA; Department of Neurology, University of California, Davis, Sacramento, CA
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18
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Hall DA, Birch RC, Anheim M, Jønch AE, Pintado E, O'Keefe J, Trollor JN, Stebbins GT, Hagerman RJ, Fahn S, Berry-Kravis E, Leehey MA. Emerging topics in FXTAS. J Neurodev Disord 2014; 6:31. [PMID: 25642984 PMCID: PMC4141265 DOI: 10.1186/1866-1955-6-31] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 04/23/2014] [Indexed: 02/07/2023] Open
Abstract
This paper summarizes key emerging issues in fragile X-associated tremor/ataxia syndrome (FXTAS) as presented at the First International Conference on the FMR1 Premutation: Basic Mechanisms & Clinical Involvement in 2013.
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Affiliation(s)
- Deborah A Hall
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Rachael C Birch
- Department of Developmental Disability Neuropsychiatry, School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Mathieu Anheim
- Département de Neurologie, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, 67098 Strasbourg, Cedex, France ; Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, 67404 Illkirch, France ; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
| | - Aia E Jønch
- Department of clinical Genetics, Kennedy Center, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Elizabeth Pintado
- Department of Medical Biochemistry and Molecular Biology, University of Seville, Sevilla, Spain
| | - Joanne O'Keefe
- Department of Anatomy & Cell Biology, Rush University, Chicago, IL, USA
| | - Julian N Trollor
- Department of Developmental Disability Neuropsychiatry, School of Psychiatry, University of New South Wales, Sydney, Australia ; Centre for Healthy Brain Ageing, University of New South Wales, Sydney, Australia
| | - Glenn T Stebbins
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Randi J Hagerman
- Department of Pediatrics & M.I.N.D. Institute, University of California at Davis Medical Center, Sacramento, CA, USA
| | - Stanley Fahn
- Department of Neurology, Columbia University, New York, NY, USA
| | - Elizabeth Berry-Kravis
- Department of Neurological Sciences, Rush University, Chicago, IL, USA ; Departments of Pediatrics and Biochemistry, Rush University, Chicago, IL, USA
| | - Maureen A Leehey
- Department of Neurology, University of Colorado at Denver, Denver, CO, USA
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19
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Grigsby J, Cornish K, Hocking D, Kraan C, Olichney JM, Rivera SM, Schneider A, Sherman S, Wang JY, Yang JC. The cognitive neuropsychological phenotype of carriers of the FMR1 premutation. J Neurodev Disord 2014; 6:28. [PMID: 25136377 PMCID: PMC4135346 DOI: 10.1186/1866-1955-6-28] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/27/2014] [Indexed: 11/10/2022] Open
Abstract
The fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder affecting a subset of carriers of the FMR1 (fragile X mental retardation 1) premutation. Penetrance and expression appear to be significantly higher in males than females. Although the most obvious aspect of the phenotype is the movement disorder that gives FXTAS its name, the disorder is also accompanied by progressive cognitive impairment. In this review, we address the cognitive neuropsychological and neurophysiological phenotype for males and females with FXTAS, and for male and female unaffected carriers. Despite differences in penetrance and expression, the cognitive features of the disorder appear similar for both genders, with impairment of executive functioning, working memory, and information processing the most prominent. Deficits in these functional systems may be largely responsible for impairment on other measures, including tests of general intelligence and declarative learning. FXTAS is to a large extent a white matter disease, and the cognitive phenotypes observed are consistent with what some have described as white matter dementia, in contrast to the impaired cortical functioning more characteristic of Alzheimer's disease and related disorders. Although some degree of impaired executive functioning appears to be ubiquitous among persons with FXTAS, the data suggest that only a subset of unaffected carriers of the premutation - both female and male - demonstrate such deficits, which typically are mild. The best-studied phenotype is that of males with FXTAS. The manifestations of cognitive impairment among asymptomatic male carriers, and among women with and without FXTAS, are less well understood, but have come under increased scrutiny.
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Affiliation(s)
- Jim Grigsby
- Department of Psychology, University of Colorado Denver, Denver, CO, USA ; Department of Medicine; Division of Health Care Policy and Research, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kim Cornish
- School of Psychology & Psychiatry; Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Darren Hocking
- Olga Tennison Autism Research Centre, School of Psychological Science, La Trobe University, Melbourne, Victoria, Australia
| | - Claudine Kraan
- School of Psychology & Psychiatry; Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - John M Olichney
- Center for Mind and Brain, University of California, Davis, CA, USA ; Department of Neurology, University of California, Davis, Sacramento, CA, USA
| | - Susan M Rivera
- Center for Mind and Brain, University of California, Davis, CA, USA ; Department of Psychology, University of California-Davis, Sacramento, CA, USA ; MIND Institute, University of California-Davis Medical Center, Sacramento, CA, USA
| | - Andrea Schneider
- Center for Mind and Brain, University of California, Davis, CA, USA ; MIND Institute, University of California-Davis Medical Center, Sacramento, CA, USA
| | | | - Jun Yi Wang
- Center for Mind and Brain, University of California, Davis, CA, USA ; Department of Pediatrics, University of California, Davis, Sacramento, CA, USA
| | - Jin-Chen Yang
- Center for Mind and Brain, University of California, Davis, CA, USA ; Department of Neurology, University of California, Davis, Sacramento, CA, USA
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20
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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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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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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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24
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Hagerman R, Hagerman P. Advances in clinical and molecular understanding of the FMR1 premutation and fragile X-associated tremor/ataxia syndrome. Lancet Neurol 2013; 12:786-98. [PMID: 23867198 DOI: 10.1016/s1474-4422(13)70125-x] [Citation(s) in RCA: 238] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fragile X syndrome, the most common heritable form of cognitive impairment, is caused by epigenetic silencing of the fragile X (FMR1) gene owing to large expansions (>200 repeats) of a non-coding CGG-repeat element. Smaller, so-called premutation expansions (55-200 repeats) can cause a family of neurodevelopmental phenotypes (attention deficit hyperactivity disorder, autism spectrum disorder, seizure disorder) and neurodegenerative (fragile X-associated tremor/ataxia syndrome [FXTAS]) phenotypes through an entirely distinct molecular mechanism involving increased FMR1 mRNA production and toxicity. Results of basic cellular, animal, and human studies have helped to elucidate the underlying RNA toxicity mechanism, while clinical research is providing a more nuanced picture of the range of clinical manifestations. Advances of knowledge on both mechanistic and clinical fronts are driving new approaches to targeted treatment, but two important necessities are emerging: to define the extent to which the mechanisms contributing to FXTAS also contribute to other neurodegenerative and medical disorders, and to redefine FXTAS in view of its differing presentations and associated features.
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Affiliation(s)
- Randi Hagerman
- Department of Pediatrics and the MIND Institute, University of California, Davis, School of Medicine, Davis, CA, USA
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25
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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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Seritan AL, Ortigas M, Seritan S, Bourgeois JA, Hagerman RJ. PSYCHIATRIC DISORDERS ASSOCIATED WITH FXTAS. ACTA ACUST UNITED AC 2013; 9:59-64. [PMID: 25620899 DOI: 10.2174/157340013805289699] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carriers of the FMR1 premutation (with 55-200 CGG repeats) may present with multiple medical and psychiatric disorders. Middle-aged carriers (males more often than females) may suffer from fragile X-associated tremor/ataxia syndrome (FXTAS). FXTAS is a newly discovered neurodegenerative disease characterized by intention tremor and ataxia, along with several other neurological features. Psychiatric manifestations are common in premutation carriers of both genders and include attention deficits, anxiety, depression, irritability, impulse dyscontrol, and substance abuse or dependence. Major depressive disorder, panic disorder with or without agoraphobia, generalized anxiety disorder, social phobia, and specific phobia are among the psychiatric diagnoses often encountered in premutation carriers, including those with FXTAS. Later in the course of the illness, cognitive deficits (including dementia) may occur. In this paper, we discuss common psychiatric phenotypes in FXTAS, based on a thorough review of the literature, as well as our own research experience. Symptomatic pharmacologic treatments are available, although disease modifying agents have not yet been developed.
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Affiliation(s)
- Andreea L Seritan
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, California ; Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California Davis Medical Center, Sacramento, California
| | - Melina Ortigas
- Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California Davis Medical Center, Sacramento, California
| | - Stefan Seritan
- University of California Santa Barbara, College for Creative Studies, Santa Barbara, California
| | - James A Bourgeois
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California Davis Medical Center, Sacramento, California ; Department of Pediatrics, University of California Davis Medical Center, Sacramento, California
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Abstract
Premutation carriers of the fragile X mental retardation gene (especially men) older than 50 may develop a neurodegenerative disease, the fragile X-associated tremor/ataxia syndrome (FXTAS). Carriers may present with varied cognitive impairments. Attention, working memory, declarative and procedural learning, information processing speed, and recall are among the cognitive domains affected. Executive dysfunction is a prominent deficit, which has been demonstrated mostly in men with FXTAS. In more advanced stages of FXTAS, both men and women may develop a mixed cortical-subcortical dementia, manifested by psychomotor slowing and deficits in attention, retrieval, recall, visuospatial skills, occasional apraxia, as well as overt personality changes. Studies have shown dementia rates as high as 37-42% in older men with FXTAS, although more research is needed to understand the prevalence and risk factors of dementia in women with FXTAS. Neuropsychiatric symptoms are common and reflect the dysfunction of underlying frontal-subcortical neural circuits, along with components of the cerebellar cognitive affective syndrome. These include labile or depressed mood, anxiety, disinhibition, impulsivity, and (rarely) psychotic symptoms. In this paper we review the information available to date regarding the prevalence and clinical picture of FXTAS dementia. Differential diagnosis may be difficult, given overlapping motor and non-motor signs with several other neurodegenerative diseases. Anecdotal response to cholinesterase inhibitors and memantine has been reported, while symptomatic treatments can address the neuropsychiatric manifestations of FXTAS dementia.
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Affiliation(s)
- Andreea Seritan
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, California
| | - Jennifer Cogswell
- Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California Davis Medical Center, Sacramento, California
| | - Jim Grigsby
- Departments of Psychology and Medicine, University of Colorado Denver, Denver, Colorado
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28
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Wang JM, Koldewyn K, Hashimoto RI, Schneider A, Le L, Tassone F, Cheung K, Hagerman P, Hessl D, Rivera SM. Male carriers of the FMR1 premutation show altered hippocampal-prefrontal function during memory encoding. Front Hum Neurosci 2012; 6:297. [PMID: 23115550 PMCID: PMC3483622 DOI: 10.3389/fnhum.2012.00297] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/08/2012] [Indexed: 01/17/2023] Open
Abstract
Previous functional MRI (fMRI) studies have shown that fragile X mental retardation 1 (FMR1) fragile X premutation allele carriers (FXPCs) exhibit decreased hippocampal activation during a recall task and lower inferior frontal activation during a working memory task compared to matched controls. The molecular characteristics of FXPCs includes 55–200 CGG trinucleotide expansions, increased FMR1 mRNA levels, and decreased FMRP levels especially at higher repeat sizes. In the current study, we utilized MRI to examine differences in hippocampal volume and function during an encoding task in young male FXPCs. While no decreases in either hippocampal volume or hippocampal activity were observed during the encoding task in FXPCs, FMRP level (measured in blood) correlated with decreases in parahippocampal activation. In addition, activity in the right dorsolateral prefrontal cortex during correctly encoded trials correlated negatively with mRNA levels. These results, as well as the established biological effects associated with elevated mRNA levels and decreased FMRP levels on dendritic maturation and axonal growth, prompted us to explore functional connectivity between the hippocampus, prefrontal cortex, and parahippocampal gyrus using a psychophysiological interaction analysis. In FXPCs, the right hippocampus evinced significantly lower connectivity with right ventrolateral prefrontal cortex (VLPFC) and right parahippocampal gyrus. Furthermore, the weaker connectivity between the right hippocampus and VLPFC was associated with reduced FMRP in the FXPC group. These results suggest that while FXPCs show relatively typical brain response during encoding, faulty connectivity between frontal and hippocampal regions may have subsequent effects on recall and working memory.
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Affiliation(s)
- John M Wang
- Virginia Tech Carilion Research Institute, Virginia Polytechnic Institute and State University Roanoke, VA, USA ; Department of Psychology, Virginia Polytechnic Institute and State University Blacksburg, VA, USA
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29
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Kaplan ES, Cao Z, Hulsizer S, Tassone F, Berman RF, Hagerman PJ, Pessah IN. Early mitochondrial abnormalities in hippocampal neurons cultured from Fmr1 pre-mutation mouse model. J Neurochem 2012; 123:613-21. [PMID: 22924671 DOI: 10.1111/j.1471-4159.2012.07936.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 07/26/2012] [Accepted: 08/14/2012] [Indexed: 12/01/2022]
Abstract
Pre-mutation CGG repeat expansions (55-200 CGG repeats; pre-CGG) within the fragile-X mental retardation 1 (FMR1) gene cause fragile-X-associated tremor/ataxia syndrome in humans. Defects in neuronal morphology, early migration, and electrophysiological activity have been described despite appreciable expression of fragile-X mental retardation protein (FMRP) in a pre-CGG knock-in (KI) mouse model. The triggers that initiate and promote pre-CGG neuronal dysfunction are not understood. The absence of FMRP in a Drosophila model of fragile-X syndrome was shown to increase axonal transport of mitochondria. In this study, we show that dissociated hippocampal neuronal culture from pre-CGG KI mice (average 170 CGG repeats) express 42.6% of the FMRP levels and 3.8-fold higher Fmr1 mRNA than that measured in wild-type neurons at 4 days in vitro. Pre-CGG hippocampal neurons show abnormalities in the number, mobility, and metabolic function of mitochondria at this early stage of differentiation. Pre-CGG hippocampal neurites contained significantly fewer mitochondria and greatly reduced mitochondria mobility. In addition, pre-CGG neurons had higher rates of basal oxygen consumption and proton leak. We conclude that deficits in mitochondrial trafficking and metabolic function occur despite the presence of appreciable FMRP expression and may contribute to the early pathophysiology in pre-CGG carriers and to the risk of developing clinical fragile-X-associated tremor/ataxia syndrome.
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Affiliation(s)
- Eitan S Kaplan
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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30
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Losh M, Klusek J, Martin GE, Sideris J, Parlier M, Piven J. Defining genetically meaningful language and personality traits in relatives of individuals with fragile X syndrome and relatives of individuals with autism. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:660-8. [PMID: 22693142 PMCID: PMC3740587 DOI: 10.1002/ajmg.b.32070] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 05/02/2012] [Indexed: 12/17/2022]
Abstract
Substantial phenotypic overlap exists between fragile X syndrome (FXS) and autism, suggesting that FMR1 (the gene causing FXS) poses a significant risk for autism. Cross-population comparisons of FXS and autism therefore offer a potentially valuable method for refining the range of phenotypes associated with variation in FMR1. This study adopted a broader phenotype approach, focusing on parents who are at increased genetic liability for autism or FXS. Women who were carriers of FMR1 in its premutation state were compared with mothers of individuals with autism, and controls in an attempt to determine whether subtle features of the broad autism phenotype may express at elevated rates among FMR1 premutation carriers. The principal personality and language features comprising the broad autism phenotype (i.e., rigid and aloof personality, and particular patterns of pragmatic language use) were assessed among 49 premutation carriers who were mothers of individuals with FXS, 89 mothers of individuals with autism, and 23 mothers of typically developing individuals. Relative to controls, the autism and premutation parent groups showed elevated rates of certain personality and language characteristics of the broad autism phenotype. Findings suggest partially overlapping personality and language profiles among autism and premutation parent groups, with rigid personality style and patterns of pragmatic language use emerging as features most clearly shared between groups. These results provide further evidence for the overlap of autism and FXS, and may implicate FMR1 in some of the subtle features comprising the broad autism phenotype.
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Affiliation(s)
- Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA.
| | - Jessica Klusek
- Division of Speech and Hearing Sciences, Department of Allied Health Sciences, University of North Carolina at Chapel Hill,Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill
| | - Gary E. Martin
- Division of Speech and Hearing Sciences, Department of Allied Health Sciences, University of North Carolina at Chapel Hill,Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill
| | - John Sideris
- Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill
| | - Morgan Parlier
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill
| | - Joseph Piven
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill
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31
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Hallahan BP, Daly EM, Simmons A, Moore CJ, Murphy KC, Murphy DDG. Fragile X syndrome: a pilot proton magnetic resonance spectroscopy study in premutation carriers. J Neurodev Disord 2012; 4:23. [PMID: 22958351 PMCID: PMC3443443 DOI: 10.1186/1866-1955-4-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 08/13/2012] [Indexed: 11/10/2022] Open
Abstract
Purpose There is increasing evidence that neurodevelopmental differences in people with Fragile X syndrome (FraX) may be explained by differences in glutamatergic metabolism. Premutation carriers of FraX were originally considered to be unaffected although several recent reports demonstrate neuroanatomical, cognitive, and emotional differences from controls. However there are few studies on brain metabolism in premutation carriers of FraX. Methods We used proton magnetic resonance spectroscopy to compare neuronal integrity of a number of brain metabolites including N-Acetyl Aspartate, Creatine + Phosphocreatinine, Choline, myoInositol, and Glutamate containing substances (Glx) in 17 male premutation carriers of FraX and 16 male healthy control individuals. Results There was no significant between-group difference in the concentration of any measured brain metabolites. However there was a differential increase in N-acetyl aspartate with aging in premutation FraX individuals compared to controls. Conclusions This is the first 1 H-MRS study to examine premutation FraX individuals. Although we demonstrated no difference in the concentration of any of the metabolites examined between the groups, this may be due to the large age ranges included in the two samples. The differential increase in NAA levels with aging may reflect an abnormal synaptic pruning process.
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Affiliation(s)
- Brian P Hallahan
- Department of Psychiatry, National University of Ireland Galway, Galway, Ireland.
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32
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Winarni TI, Chonchaiya W, Sumekar TA, Ashwood P, Morales GM, Tassone F, Nguyen DV, Faradz SMH, Van de Water J, Cook K, Hamlin A, Mu Y, Hagerman PJ, Hagerman RJ. Immune-mediated disorders among women carriers of fragile X premutation alleles. Am J Med Genet A 2012; 158A:2473-81. [PMID: 22903889 DOI: 10.1002/ajmg.a.35569] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 06/20/2012] [Indexed: 12/14/2022]
Abstract
The relative risk of immune-mediated disorders (IMDs) among women carriers of premutation alleles is estimated by a survey for IMDs among 344 carrier women (age 19-81 years; mean 46.35 and SD 12.60) and 72 controls (age 18-87 years; mean 52.40 and SD 15.40). One hundred fifty four (44.77%) women carrier had at least one IMD, as did 20 controls (27.78%). Among women carriers, autoimmune thyroid disorder was the most common (24.4%), then fibromyalgia (10.2%), irritable bowel syndrome (IBS; 9.9%), Raynaud's phenomenon (7.6%), rheumatoid arthritis (RA; 3.8%), Sjögren syndrome (2.6%), systemic lupus erythematosus (SLE; 2.03%), multiple sclerosis (1.74%). Of 55 carriers age 40 or older with FXTAS, 72.73% had at least one IMD, compared to 46.54% of those without FXTAS (n = 159), and 31.58% of controls (n = 57). The estimated odds ratio (OR) for IMD is 2.6 (95% CI 1.2-5.6, P = 0.015) for women with FXTAS relative to those without FXTAS; the likelihood of IMD in carriers without or with FXTAS was also significantly higher than for controls (OR 2.1, 95% CI 1.1-4.2, P = 0.034; OR 5.5, 95% CI 2.4-12.5, P < 0.001, respectively). Similarly, the odds of having an IMD among carriers with FXPOI is about 2.4 times higher when compared to carriers without FXPOI (95% CI 1.1-5.0; P = 0.021). The likelihood of IMD in carriers with or without FXPOI is greater (OR 2.4, 95% CI 1.1-5.0; P = 0.021) compared to that of controls.
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Affiliation(s)
- Tri Indah Winarni
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California, Davis, Health System, Sacramento, USA
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33
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Finucane B, Abrams L, Cronister A, Archibald AD, Bennett RL, McConkie-Rosell A. Genetic Counseling and Testing for FMR1 Gene Mutations: Practice Guidelines of the National Society of Genetic Counselors. J Genet Couns 2012; 21:752-60. [DOI: 10.1007/s10897-012-9524-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 06/22/2012] [Indexed: 11/25/2022]
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Schneider A, Ballinger E, Chavez A, Tassone F, Hagerman RJ, Hessl D. Prepulse inhibition in patients with fragile X-associated tremor ataxia syndrome. Neurobiol Aging 2012; 33:1045-53. [PMID: 20961665 PMCID: PMC3044775 DOI: 10.1016/j.neurobiolaging.2010.09.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 08/23/2010] [Accepted: 09/05/2010] [Indexed: 11/25/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late onset neurodegenerative disorder that affects carriers of the fragile X premutation, typically after age 50. Common symptoms include intention tremor, ataxia, neuropathy, autonomic dysfunction, cognitive decline, and dementia. The objectives of this study were to determine if patients with FXTAS have altered prepulse inhibition (PPI; a measure of sensorimotor gating), and to study possible correlations between PPI, molecular status, and cognitive performance. A passive acoustic PPI paradigm was applied in 163 subjects; 121 carriers of the fragile X premutation, and 42 healthy controls. There were significant differences in PPI between premutation carriers with FXTAS and controls at PPI 60 ms, and at 120 ms. This effect was more prominent in the male FXTAS patients. There was a tendency to an impaired PPI in female premutation carriers at the 120 ms condition. There was a significant correlation between the PPI deficit and a higher CGG repeat number. The results show an impairment in sensorimotor gating processes in male carriers of the fragile X premutation, which is more prominent in patients with FXTAS.
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Affiliation(s)
- Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute, University of California at Davis, Sacramento, CA 95817, USA.
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35
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Spatiotemporal processing deficits in female CGG KI mice modeling the fragile X premutation. Behav Brain Res 2012; 233:29-34. [PMID: 22561129 DOI: 10.1016/j.bbr.2012.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 04/12/2012] [Accepted: 04/20/2012] [Indexed: 01/05/2023]
Abstract
The fragile X premutation is a tandem CGG trinucleotide repeat expansion in the fragile X mental retardation 1 (FMR1) gene between 55 and 200 repeats in length. A CGG knock-in (CGG KI) mouse has been developed that models the neuropathology and cognitive deficits reported in fragile X premutation carriers. It has been suggested that carriers of the premutation demonstrate a spatiotemporal hypergranularity, or reduced resolution of spatial and temporal processing. A temporal ordering of spatial locations task was used to evaluate the ability of CGG KI mice to process temporal and spatial information with either high or low levels of spatial interference. The results indicate that CGG KI mice showed difficulty performing a spatial novelty detection task when there were high levels of spatial interference, but were able to perform the novelty detection task when there was low spatial interference. These data suggest that CGG KI mice show reduced spatial and temporal resolution that are modulated by the dosage of the Fmr1 gene mutation, such that when behavioral tasks require mice to overcome high levels of either spatial or temporal interference, the CGG KI mice perform increasingly poorly as the CGG repeat length increases.
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Tassone F, Greco CM, Hunsaker MR, Seritan AL, Berman RF, Gane LW, Jacquemont S, Basuta K, Jin LW, Hagerman PJ, Hagerman RJ. Neuropathological, clinical and molecular pathology in female fragile X premutation carriers with and without FXTAS. GENES BRAIN AND BEHAVIOR 2012; 11:577-85. [PMID: 22463693 DOI: 10.1111/j.1601-183x.2012.00779.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder associated with premutation alleles of the fragile X mental retardation 1 (FMR1) gene. Approximately 40% of older male premutation carriers, and a smaller proportion of females, are affected by FXTAS; due to the lower penetrance the characterization of the disorder in females is much less detailed. Core clinical features of FXTAS include intention tremor, cerebellar gait ataxia and frequently parkinsonism, autonomic dysfunction and cognitive deficits progressing to dementia in up to 50% of males. In this study, we report the clinical, molecular and neuropathological findings of eight female premutation carriers. Significantly, four of these women had dementia; of the four, three had FXTAS plus dementia. Post-mortem examination showed the presence of intranuclear inclusions in all eight cases, which included one asymptomatic premutation carrier who died from cancer. Among the four subjects with dementia, three had sufficient number of cortical amyloid plaques and neurofibrillary tangles to make Alzheimer's disease a highly likely cause of dementia and a fourth case had dementia with cortical Lewy bodies. Dementia appears to be more common than originally reported in females with FXTAS. Although further studies are required, our observation suggests that in a portion of FXTAS cases there is Alzheimer pathology and perhaps a synergistic effect on the progression of the disease may occur.
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Affiliation(s)
- F Tassone
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, USA.
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Abstract
Premutation fragile X carriers have a CGG repeat expansion (55 to 200 repeats) in the promoter region of the fragile X mental retardation 1 (FMR1) gene. Amygdala dysfunction has been observed in premutation symptomatology, and recent research has suggested the amygdala as an area susceptible to the molecular effects of the premutation. The current study utilizes structural magnetic resonance imaging (MRI) to examine the relationship between amygdala volume, CGG expansion size, FMR1 mRNA, and psychological symptoms in male premutation carriers without FXTAS compared with age and IQ matched controls. No significant between group differences in amygdala volume were found. However, a significant negative correlation between amygdala volume and CGG was found in the lower range of CGG repeat expansions, but not in the higher range of CGG repeat expansions.
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Hunsaker MR. Comprehensive neurocognitive endophenotyping strategies for mouse models of genetic disorders. Prog Neurobiol 2012; 96:220-41. [PMID: 22266125 PMCID: PMC3289520 DOI: 10.1016/j.pneurobio.2011.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 12/06/2011] [Accepted: 12/20/2011] [Indexed: 01/21/2023]
Abstract
There is a need for refinement of the current behavioral phenotyping methods for mouse models of genetic disorders. The current approach is to perform a behavioral screen using standardized tasks to define a broad phenotype of the model. This phenotype is then compared to what is known concerning the disorder being modeled. The weakness inherent in this approach is twofold: First, the tasks that make up these standard behavioral screens do not model specific behaviors associated with a given genetic mutation but rather phenotypes affected in various genetic disorders; secondly, these behavioral tasks are insufficiently sensitive to identify subtle phenotypes. An alternate phenotyping strategy is to determine the core behavioral phenotypes of the genetic disorder being studied and develop behavioral tasks to evaluate specific hypotheses concerning the behavioral consequences of the genetic mutation. This approach emphasizes direct comparisons between the mouse and human that facilitate the development of neurobehavioral biomarkers or quantitative outcome measures for studies of genetic disorders across species.
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Affiliation(s)
- Michael R Hunsaker
- Department of Neurological Surgery, University of California, Davis, Davis, CA 95616, USA.
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Hunsaker MR, Greco CM, Spath MA, Smits APT, Navarro CS, Tassone F, Kros JM, Severijnen LA, Berry-Kravis EM, Berman RF, Hagerman PJ, Willemsen R, Hagerman RJ, Hukema RK. Widespread non-central nervous system organ pathology in fragile X premutation carriers with fragile X-associated tremor/ataxia syndrome and CGG knock-in mice. Acta Neuropathol 2011; 122:467-79. [PMID: 21785977 DOI: 10.1007/s00401-011-0860-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 07/11/2011] [Accepted: 07/11/2011] [Indexed: 11/28/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder generally presenting with intention tremor and gait ataxia, but with a growing list of co-morbid medical conditions including hypothyroidism, hypertension, peripheral neuropathy, and cognitive decline. The pathological hallmark of FXTAS is the presence of intranuclear inclusions in both neurons and astroglia. However, it is unknown to what extent such inclusions are present outside the central nervous system (CNS). To address this issue, we surveyed non-CNS organs in ten human cases with FXTAS and in a CGG repeat knock-in (CGG KI) mouse model known to possess neuronal and astroglial inclusions. We find inclusions in multiple tissues from FXTAS cases and CGG KI mice, including pancreas, thyroid, adrenal gland, gastrointestinal, pituitary gland, pineal gland, heart, and mitral valve, as well as throughout the associated autonomic ganglia. Inclusions were observed in the testes, epididymis, and kidney of FXTAS cases, but were not observed in mice. These observations demonstrate extensive involvement of the peripheral nervous system and systemic organs. The finding of intranuclear inclusions in non-CNS somatic organ systems, throughout the PNS, and in the enteric nervous system of both FXTAS cases as well as CGG KI mice suggests that these tissues may serve as potential sites to evaluate early intervention strategies or be used as diagnostic factors.
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Affiliation(s)
- Michael R Hunsaker
- Department of Neurological Surgery, University of California, Davis, Davis, CA, USA
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Gallagher A, Hallahan B. Fragile X-associated disorders: a clinical overview. J Neurol 2011; 259:401-13. [PMID: 21748281 DOI: 10.1007/s00415-011-6161-3] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 06/24/2011] [Accepted: 06/25/2011] [Indexed: 01/13/2023]
Abstract
Fragile X Syndrome (FraX) is the most common inherited cause of learning disability worldwide. FraX is an X-linked neuro-developmental disorder involving an unstable trinucleotide repeat expansion of cytosine guanine guanine (CGG). Individuals with the full mutation of FraX have >200 GG repeats with premutation carriers having 55-200 GG repeats. A wide spectrum of physical, behavioural, cognitive, psychiatric and medical problems have been associated with both full mutation and premutation carriers of FraX. In this review, we detail the clinical profile and examine the aetiology, epidemiology, neuropathology, neuroimaging findings and possible management strategies for individuals with both the full mutation and premutation of FraX.
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Affiliation(s)
- Anne Gallagher
- Department of Psychiatry, Clinical Science Institute, National University of Ireland Galway, Galway, Ireland
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FMR1 premutation and full mutation molecular mechanisms related to autism. J Neurodev Disord 2011; 3:211-24. [PMID: 21617890 PMCID: PMC3261276 DOI: 10.1007/s11689-011-9084-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 05/09/2011] [Indexed: 11/10/2022] Open
Abstract
Fragile X syndrome (FXS) is caused by an expanded CGG repeat (>200 repeats) in the 5′ un-translated portion of the fragile X mental retardation 1 gene (FMR1) leading to a deficiency or absence of the FMR1 protein (FMRP). FMRP is an RNA-binding protein that regulates the translation of a number of other genes that are important for synaptic development and plasticity. Furthermore, many of these genes, when mutated, have been linked to autism in the general population, which may explain the high comorbidity that exists between FXS and autism spectrum disorders (ASD). Additionally, premutation repeat expansions (55 to 200 CGG repeats) may also give rise to ASD through a different molecular mechanism that involves a direct toxic effect of FMR1 mRNA. It is believed that RNA toxicity underlies much of the premutation-related involvement, including developmental concerns like autism, as well as neurodegenerative issues with aging such as the fragile X-associated tremor ataxia syndrome (FXTAS). RNA toxicity can also lead to mitochondrial dysfunction, which is common in older premutation carriers both with and without FXTAS. Many of the problems with cellular dysregulation in both premutation and full mutation neurons also parallel the cellular abnormalities that have been documented in idiopathic autism. Research regarding dysregulation of neurotransmitter systems caused by the lack of FMRP in FXS, including metabotropic glutamate receptor 1/5 (mGluR1/5) pathway and GABA pathways, has led to new targeted treatments for FXS. Preliminary evidence suggests that these new targeted treatments will also be beneficial in non-fragile X forms of autism.
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A Quantitative Assessment of Tremor and Ataxia in Female FMR1 Premutation Carriers Using CATSYS. Curr Gerontol Geriatr Res 2011; 2011:484713. [PMID: 23008705 PMCID: PMC3114433 DOI: 10.1155/2011/484713] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Accepted: 02/28/2011] [Indexed: 11/21/2022] Open
Abstract
The fragile X-associated tremor/ataxia syndrome (FXTAS) is a relatively common cause of balance problems leading to gait disturbances in older males (40%) with the premutation. FXTAS is less common in females. We utilized the CATSYS system, a quantitative measure of movement, in 23 women with FXTAS (mean age 62.7; SD 12.3), 90 women with the premutation without FXTAS (mean age 52.9; SD 9.4), and 37 controls (mean age 56.53; SD 7.8). CATSYS distinguished differences between carriers with and without FXTAS in postural tremor, postural sway, hand coordination, and reaction time tasks. Differences were also seen between carriers without FXTAS and controls in finger tapping, reaction time, and one postural sway task. However, these differences did not persist after statistical correction for multiple comparisons. Notably, there were no differences across groups in intention tremor. This is likely due to the milder symptoms in females compared to males with FXTAS.
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Hashimoto RI, Javan AK, Tassone F, Hagerman RJ, Rivera SM. A voxel-based morphometry study of grey matter loss in fragile X-associated tremor/ataxia syndrome. Brain 2011; 134:863-78. [PMID: 21354978 DOI: 10.1093/brain/awq368] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome is a neurodegenerative disorder that primarily affects older male premutation carriers of the fragile X mental retardation gene. Although its core symptoms are mainly characterized by motor problems such as intention tremor and gait ataxia, cognitive decline and psychiatric problems are also commonly observed. Past radiological and histological approaches have focused on prominent neurodegenerative changes in specific brain structures including the cerebellum and limbic areas. However, quantitative investigations of the regional structural abnormalities have not been performed over the whole brain. In this study, we adopted the voxel-based morphometry method together with regions of interest analysis for the cerebellum to examine the pattern of regional grey matter change in the male premutation carriers with and without fragile X-associated tremor/ataxia syndrome. In a comparison with healthy controls, we found striking grey matter loss of the patients with fragile X-associated tremor/ataxia syndrome in multiple regions over the cortical and subcortical structures. In the cerebellum, the anterior lobe and the superior posterior lobe were profoundly reduced in both vermis and hemispheres. In the cerebral cortex, clusters of highly significant grey matter reduction were found in the extended areas in the medial surface of the brain, including the dorsomedial prefrontal cortex, anterior cingulate cortex and precuneus. The other prominent grey matter loss was found in the lateral prefrontal cortex, orbitofrontal cortex, amygdala and insula. Although the voxel-wise comparison between the asymptomatic premutation group and healthy controls did not reach significant difference, a regions of interest analysis revealed significant grey matter reduction in anterior subregions of the cerebellar vermis and hemisphere in the asymptomatic premutation group. Correlation analyses using behavioural scales of the premutation groups showed significant associations between grey matter loss in the left amygdala and increased levels of obsessive-compulsiveness and depression, and between decreased grey matter in the left inferior frontal cortex and anterior cingulate cortex and poor working memory performance. Furthermore, regression analyses revealed a significant negative effect of CGG repeat size on grey matter density in the dorsomedial frontal regions. A significant negative correlation with the clinical scale for the severity of fragile X-associated tremor/ataxia syndrome was found in a part of the vermis. These observations reveal the anatomical patterns of the neurodegenerative process that underlie the motor, cognitive and psychiatric problems of fragile X-associated tremor/ataxia syndrome, together with incipient structural abnormalities that may occur before the clinical onset of this disease.
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Affiliation(s)
- Ryu-ichiro Hashimoto
- Center for Mind and Brain, University of California Davis, 267 Cousteau Place, Davis, CA 95618-5412, USA
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Hunsaker MR, von Leden RE, Ta BT, Goodrich-Hunsaker NJ, Arque G, Kim K, Willemsen R, Berman RF. Motor deficits on a ladder rung task in male and female adolescent and adult CGG knock-in mice. Behav Brain Res 2011; 222:117-21. [PMID: 21440572 DOI: 10.1016/j.bbr.2011.03.039] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 03/14/2011] [Accepted: 03/17/2011] [Indexed: 11/19/2022]
Abstract
The fragile X premutation is a tandem CGG trinucleotide repeat expansion on the FMR1 gene between 55 and 200 repeats in length. A CGG knock-in (CGG KI) mouse with CGG trinucleotide repeat lengths between 70 and 350 has been developed and used to model the histopathology and cognitive deficits reported in carriers of the fragile X premutation. Previous studies have shown that CGG KI mice show progressive deficits in processing spatial and temporal information. To characterize the motor deficits associated with the fragile X premutation, male and female CGG KI mice ranging from 2 to 16 months of age with trinucleotide repeats ranging from 72 to 240 CGG in length were tested for their ability to perform a skilled ladder rung walking test. The results demonstrate that both male and female CGG KI mice showed a greater number of foot slips as a function of increased CGG repeat length, independent of the age of the animal or general activity level.
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Affiliation(s)
- Michael R Hunsaker
- Department of Neurological Surgery, School of Medicine, University of California, Davis; Davis, CA 95616, USA.
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46
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Wang LW, Berry-Kravis E, Hagerman RJ. Fragile X: leading the way for targeted treatments in autism. Neurotherapeutics 2010; 7:264-74. [PMID: 20643379 PMCID: PMC4084556 DOI: 10.1016/j.nurt.2010.05.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 05/19/2010] [Accepted: 05/22/2010] [Indexed: 10/19/2022] Open
Abstract
Two different mutations in the FMR1 gene may lead to autism. The full mutation, with >200 CGG repeats in the 5' end of FMR1, leads to hypermethylation and transcriptional silencing of FMR1, resulting in absence or deficiency of the protein product, FMRP. Deficiency of FMRP in the brain causes fragile X syndrome (FXS). Autism occurs in approximately 30% of those with FXS, and pervasive developmental disorders-not otherwise specified occur in an additional 30%. FMRP is an RNA binding protein that modulates receptor-mediated dendritic translation; deficiency leads to dysregulation of many proteins important for synaptic plasticity. Group I metabotropic glutamate receptor (mGluR1/5) activated translation is upregulated in FXS, and new targeted treatments that act on this system include mGluR5 antagonists and GABA agonists, which may reverse the cognitive and behavioral deficits in FXS. Matrix metalloproteinase 9 (MMP-9) is one of the proteins elevated in FXS, and minocycline reduces excess MMP-9 activity in the Fmr1 knockout mouse model of FXS. Both minocycline and mGluR5 antagonists are currently being evaluated in patients with FXS through controlled treatment trials. The premutation (55-200 CGG repeats) may also contribute to the mechanism of autism in approximately 10% of males and 2-3% of females. Premutations with <150 repeats exert cellular effects through a different molecular mechanism, one that involves elevated levels of FMR1 mRNA, CGG-mediated toxicity to neurons, early cell death, and fragile X-associated tremor/ataxia syndrome. In those with large premutations (150-200), lowered levels of FMRP also occur.
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Affiliation(s)
- Lulu W Wang
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, California 95817, USA.
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Hunsaker MR, Goodrich-Hunsaker NJ, Willemsen R, Berman RF. Temporal ordering deficits in female CGG KI mice heterozygous for the fragile X premutation. Behav Brain Res 2010; 213:263-8. [PMID: 20478339 DOI: 10.1016/j.bbr.2010.05.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 04/30/2010] [Accepted: 05/07/2010] [Indexed: 01/27/2023]
Abstract
The fragile X premutation is a tandem CGG trinucleotide repeat expansion on the FMR1 gene between 55 and 200 repeats in length. A CGG knock-in (CGG KI) mouse with CGG repeat lengths between 70 and 350 has been developed and used to characterize the histopathology and cognitive deficits reported in carriers of the fragile X premutation. Previous studies have shown that CGG KI mice show progressive deficits in processing spatial information. To further characterize cognitive deficits in the fragile X premutation, temporal ordering in CGG knock-in (CGG KI) mice was evaluated. Female CGG KI mice were tested for their ability to remember the temporal order in which two objects were presented. The results demonstrate that at 48 weeks of age, female CGG KI mice with CGG repeat expansions between 150 and 200 CGG repeats performed more poorly on tests of temporal order than wildtype mice, whereas female CGG KI mice with between 80 and 100 CGG repeats performed similarly to wildtype mice. No mice had any difficulty in detecting the presence of a novel object. These data suggest female CGG KI mice show a CGG repeat length-sensitive deficit for temporal ordering.
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Affiliation(s)
- Michael R Hunsaker
- Program in Neuroscience, University of California-Davis, 1515 Newton Court, Davis, CA 95616, USA.
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Garcia-Arocena D, Hagerman PJ. Advances in understanding the molecular basis of FXTAS. Hum Mol Genet 2010; 19:R83-9. [PMID: 20430935 DOI: 10.1093/hmg/ddq166] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder among carriers of premutation expansions (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene. The clinical features of FXTAS, as well as other forms of clinical involvement in carriers without FXTAS, are thought to arise from a toxic gain of function of transcriptionally active FMR1 containing expanded CGG repeats. Although the precise mechanisms involved in rCGG toxicity are unknown, here we discuss the latest advances and models that contribute to the understanding of the molecular basis of FXTAS, and the emerging view of FXTAS as the end-stage of a process that begins in early development.
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Affiliation(s)
- Dolores Garcia-Arocena
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA, USA
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