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Shelton AL, Cornish K, Clough M, Gajamange S, Kolbe S, Fielding J. Disassociation between brain activation and executive function in fragile X premutation females. Hum Brain Mapp 2016; 38:1056-1067. [PMID: 27739609 DOI: 10.1002/hbm.23438] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 09/28/2016] [Accepted: 10/05/2016] [Indexed: 11/11/2022] Open
Abstract
Executive dysfunction has been demonstrated among premutation (PM) carriers (55-199 CGG repeats) of the Fragile X mental retardation 1 (FMR1) gene. Further, alterations to neural activation patterns have been reported during memory and comparison based functional magnetic resonance imaging (fMRI) tasks in these carriers. For the first time, the relationships between fMRI neural activation during an interleaved ocular motor prosaccade/antisaccade paradigm, and concurrent task performance (saccade measures of latency, accuracy and error rate) in PM females were examined. Although no differences were found in whole brain activation patterns, regions of interest (ROI) analyses revealed reduced activation in the right ventrolateral prefrontal cortex (VLPFC) during antisaccade trials for PM females. Further, a series of divergent and group specific relationships were found between ROI activation and saccade measures. Specifically, for control females, activation within the right VLPFC and supramarginal gyrus correlated negatively with antisaccade latencies, while for PM females, activation within these regions was found to negatively correlate with antisaccade accuracy and error rate (right VLPFC only). For control females, activation within frontal and supplementary eye fields and bilateral intraparietal sulci correlated with prosaccade latency and accuracy; however, no significant prosaccade correlations were found for PM females. This exploratory study extends previous reports of altered prefrontal neural engagement in PM carriers, and clearly demonstrates dissociation between control and PM females in the transformation of neural activation into overt measures of executive dysfunction. Hum Brain Mapp 38:1056-1067, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Annie L Shelton
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Kim Cornish
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Meaghan Clough
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Sanuji Gajamange
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Scott Kolbe
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Joanne Fielding
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
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Wong LM, Goodrich-Hunsaker NJ, McLennan YA, Tassone F, Rivera SM, Simon TJ. A cross-sectional analysis of orienting of visuospatial attention in child and adult carriers of the fragile X premutation. J Neurodev Disord 2014; 6:45. [PMID: 25937844 PMCID: PMC4416306 DOI: 10.1186/1866-1955-6-45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 11/15/2014] [Indexed: 11/13/2022] Open
Abstract
Background Fragile X premutation carriers (fXPCs) have an expansion of 55–200 CGG repeats in the FMR1 gene. Male fXPCs are at risk for developing a neurodegenerative motor disorder (fragile X-associated tremor/ataxia syndrome (FXTAS)) often accompanied by cognitive decline. Several broad domains are implicated as core systems of dysfunction in fXPCs, including perceptual processing of spatial information, orienting of attention to space, and inhibiting attention to irrelevant distractors. We tested whether orienting of spatial attention is impaired in fXPCs. Methods Participants were fXPCs or healthy controls (HCs) asymptomatic for FXTAS. In experiment 1, they were male and female children and adults (aged 7–45 years). They oriented attention in response to volitional (endogenous) and reflexive (exogenous) cues. In experiment 2, the participants were men (aged 18–48 years). They oriented attention in an endogenous cueing task that manipulated the amount of information in the cue. Results In women, fXPCs exhibited slower reaction times than HCs in both the endogenous and exogenous conditions. In men, fXPCs exhibited slower reaction times than HCs in the exogenous condition and in the challenging endogenous cueing task with probabilistic cues. In children, fXPCs did not differ from HCs. Conclusions Because adult fXPCs were slower even when controlling for psychomotor speed, results support the interpretation that a core dysfunction in fXPCs is the allocation of spatial attention, while perceptual processing and attention orienting are intact. These findings indicate the importance of considering age and sex when interpreting and generalizing studies of fXPCs.
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Affiliation(s)
- Ling M Wong
- Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA ; War Related Illness and Injury Study Center, Veterans Affairs Medical Center, Washington, DC 20422 USA
| | | | - Yingratana A McLennan
- Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA
| | - Flora Tassone
- Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA ; Department of Biochemistry and Molecular Medicine, University of California, Davis Medical Center, Sacramento, CA 95817 USA
| | - Susan M Rivera
- Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA ; Department of Psychology, University of California, Davis, CA 95616 USA ; Center for Mind and Brain, University of California, Davis, CA 95616 USA
| | - Tony J Simon
- Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, University of California, Davis Medical Center, Sacramento, CA 95817 USA
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3
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Language dysfluencies in females with the FMR1 premutation. Brain Cogn 2013; 82:84-9. [PMID: 23523717 DOI: 10.1016/j.bandc.2013.02.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 02/17/2013] [Accepted: 02/18/2013] [Indexed: 11/21/2022]
Abstract
Recent evidence suggests that there are age-related neurocognitive implications for fragile X premutation carriers, including deficits in executive function, and that such deficits are more common in male than female premutation carriers. The purpose of the current study is to examine one aspect of executive function, language dysfluencies, in a group of 193 women with the premutation, and to contrast them with a comparison group (mothers of children with autism spectrum disorders). Our results demonstrate a linguistic profile in the female premutation carriers characterized by dysfluencies associated with deficits in organization and planning, with a clear impact of age. The comparison group, matched on both age and education level, did not demonstrate the age effect. Our results suggest dysfluencies could be an early indicator of cognitive aging in some female premutation carriers, and could be used to target early intervention.
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Neurobehavioural evidence for the involvement of the FMR1 gene in female carriers of fragile X syndrome. Neurosci Biobehav Rev 2013; 37:522-47. [DOI: 10.1016/j.neubiorev.2013.01.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 12/11/2012] [Accepted: 01/06/2013] [Indexed: 12/19/2022]
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Young adult male carriers of the fragile X premutation exhibit genetically modulated impairments in visuospatial tasks controlled for psychomotor speed. J Neurodev Disord 2012; 4:26. [PMID: 23148490 PMCID: PMC3506571 DOI: 10.1186/1866-1955-4-26] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 10/25/2012] [Indexed: 02/04/2023] Open
Abstract
Background A previous study reported enhanced psychomotor speed, and subtle but significant cognitive impairments, modulated by age and by mutations in the fragile X mental retardation 1 (FMR1) gene in adult female fragile X premutation carriers (fXPCs). Because male carriers, unlike females, do not have a second, unaffected FMR1 allele, male fXPCs should exhibit similar, if not worse, impairments. Understanding male fXPCs is of particular significance because of their increased risk of developing fragile X-associated tremor/ataxia syndrome (FXTAS). Methods Male fXPCs (n = 18) and healthy control (HC) adults (n = 26) aged less than 45 years performed two psychomotor speed tasks (manual and oral) and two visuospatial tasks (magnitude comparison and enumeration). In the magnitude comparison task, participants were asked to compare and judge which of two bars was larger. In the enumeration task, participants were shown between one and eight green bars in the center of the screen, and asked to state the total number displayed. Enumeration typically proceeds in one of two modes: subitizing, a fast and accurate process that works only with a small set of items, and counting, which requires accurate serial-object detection and individuation during visual search. We examined the associations between the performance on all tasks and the age, full-scale intelligent quotient, and CGG repeat length of participants. Results We found that in the magnitude comparison and enumeration tasks, male fXPCs exhibited slower reaction times relative to HCs, even after controlling for simple reaction time. Conclusions Our results indicate that male fXPCs as a group show impairments (slower reaction times) in numerical visuospatial tasks, which are consistent with previous findings. This adds to a growing body of literature characterizing the phenotype in fXPCs who are asymptomatic for FXTAS. Future longitudinal studies are needed to determine how these impairments relate to risk of developing FXTAS.
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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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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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Loesch D, Hagerman R. Unstable Mutations in the FMR1 Gene and the Phenotypes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 769:78-114. [DOI: 10.1007/978-1-4614-5434-2_6] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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Pirozzi F, Tabolacci E, Neri G. The FRAXopathies: definition, overview, and update. Am J Med Genet A 2011; 155A:1803-16. [PMID: 21739597 DOI: 10.1002/ajmg.a.34113] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 04/22/2011] [Indexed: 01/12/2023]
Abstract
The fragile X syndrome, fragile X tremor ataxia syndrome, and premature ovarian insufficiency are conditions related to the X chromosome folate-sensitive fragile site FRAXA. Therefore, we propose that they are considered as a family of disorders under the general designation of FRAXopathies. The present review will outline the main clinical and molecular features of these disorders, with special emphasis on the pathogenic mechanisms that lead to distinct phenotypes, starting from related mutations. The understanding of these mechanisms is already generating promising therapeutic approaches.
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Hashimoto RI, Backer KC, Tassone F, Hagerman RJ, Rivera SM. An fMRI study of the prefrontal activity during the performance of a working memory task in premutation carriers of the fragile X mental retardation 1 gene with and without fragile X-associated tremor/ataxia syndrome (FXTAS). J Psychiatr Res 2011; 45:36-43. [PMID: 20537351 PMCID: PMC2978252 DOI: 10.1016/j.jpsychires.2010.04.030] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 04/23/2010] [Accepted: 04/30/2010] [Indexed: 01/25/2023]
Abstract
Premutation alleles of the fragile X mental retardation 1 gene (FMR1) are associated with the risk of developing fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder that involves neuropsychiatric problems and executive and memory deficits. Although abnormal elevation of FMR1 mRNA has been proposed to underlie these deficits, it remains unknown which brain regions are affected by the disease process of FXTAS and genetic molecular mechanisms associated with the FMR1 premutation. This study used functional magnetic resonance imaging (fMRI) to identify deficient neural substrates responsible for altered executive and memory functions in some FMR1 premutation individuals. We measured fMRI BOLD signals during the performance of verbal working memory from 15 premutation carriers affected by FXTAS (PFX+), 15 premutation carriers unaffected by FXTAS (PFX-), and 12 matched healthy control individuals (HC). We also examined correlation between brain activation and FMR1 molecular variables (CGG repeat size and mRNA levels) in premutation carriers. Compared with HC, PFX+ and PFX- showed reduced activation in the right ventral inferior frontal cortex and left premotor/dorsal inferior frontal cortex. Reduced activation specific to PFX+ was found in the right premotor/dorsal inferior frontal cortex. Regression analysis combining the two premutation groups demonstrated significant negative correlation between the right ventral inferior frontal cortex activity and the levels of FMR1 mRNA after excluding the effect of disease severity of FXTAS. These results indicate altered prefrontal cortex activity that may underline executive and memory deficits affecting some individuals with FMR1 premutation including FXTAS patients.
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Affiliation(s)
| | | | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorder (MIND), University of California Medical Center, Sacramento, USA
- Department of Biochemistry and Molecular Medicine, University of California, Davis, USA
| | - Randi J. Hagerman
- Medical Investigation of Neurodevelopmental Disorder (MIND), University of California Medical Center, Sacramento, USA
- Department of Pediatrics, University of California School of Medicine, Davis, USA
| | - Susan M. Rivera
- Center for Mind and Brain, University of California, Davis, USA
- Medical Investigation of Neurodevelopmental Disorder (MIND), University of California Medical Center, Sacramento, USA
- Department of Psychology University of California, Davis, USA
- Address correspondence and reprint request to Dr. Susan M. Rivera, Center for Mind and Brain, University of California, Davis, 220 Cousteau Place, Suite 250, Davis, CA, 95618. Tel: (530) 747-3802 Fax: (530) 297-4603
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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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12
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Bourgeois J, Coffey S, Rivera SM, Hessl D, Gane LW, Tassone F, Greco C, Finucane B, Nelson L, Berry-Kravis E, Grigsby J, Hagerman PJ, Hagerman RJ. A review of fragile X premutation disorders: expanding the psychiatric perspective. J Clin Psychiatry 2009; 70:852-62. [PMID: 19422761 PMCID: PMC2705685 DOI: 10.4088/jcp.08m04476] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 11/11/2008] [Indexed: 01/28/2023]
Abstract
CONTEXT Fragile X premutation conditions are associated with a significant degree of psychopathology and thus are of interest to the psychiatrist. Remarkable advances at the molecular level have enhanced our understanding of fragile X premutation disorders. OBJECTIVE The authors review the genetic, molecular, neuroimaging, and clinical (systemic, neurologic, and psychiatric) manifestations of the premutation carrier state (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene. DATA SOURCES The search for the psychiatric clinical manifestations of fragile X-associated conditions was accomplished by PubMed for clinical papers published between 1970 and 2008 with the following search terms: Fragile X syndrome, depression, psychosis, anxiety, and dementia. STUDY SELECTION Articles addressing psychiatric symptoms in premutation carriers based on review of the abstracts were reviewed. As the majority of the literature on this topic is based on case reports and small case series, these were included in the database. RESULTS Reported clinical manifestations of psychiatric illness in premutation carriers include an apparently significant rate of cognitive, mood, anxiety, and other psychiatric disorders. Fragile X premutation-associated conditions are part of the clinical differential diagnosis of several psychiatric syndromes, particularly in pedigrees with known fragile X syndrome cases. CONCLUSIONS Fragile X-associated psychiatric manifestations serve as a useful model for a molecular genesis of neuropsychiatric illness. Because of the multigenerational expression of fragile X-associated neuropsychiatric illness, there is a prominent role for genetic testing and genetic counseling of patients and their relatives. Genetic testing is confirmatory of the FMR1 premutation and is an essential component of the clinical evaluation. Psychopharmacologic and psychotherapeutic treatment of fragile X-associated psychiatric illnesses may improve patient function and assist in adaptation to the burden of a genetic neuropsychiatric illness.
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Affiliation(s)
- James Bourgeois
- Department of Psychiatry and Behavioral Sciences, University of California, Davis Medical Center, Sacramento, CA
| | - Sarah Coffey
- M.I.N.D. Institute, University of California, Davis Medical Center, Sacramento, CA., Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA
| | - Susan M. Rivera
- M.I.N.D. Institute, University of California, Davis Medical Center, Sacramento, CA., Department of Psychology, University of California, Davis
| | - David Hessl
- M.I.N.D. Institute, University of California, Davis Medical Center, Sacramento, CA., Department of Psychiatry and Behavioral Sciences, University of California, Davis, Sacramento, CA
| | - Louise W. Gane
- M.I.N.D. Institute, University of California, Davis Medical Center, Sacramento, CA
| | - Flora Tassone
- M.I.N.D. Institute, University of California, Davis Medical Center, Sacramento, CA., Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, CA
| | - Claudia Greco
- Department of Pathology, University of California, Davis Medical Center, School of Medicine, Sacramento, CA
| | - Brenda Finucane
- Genetic Services, Elwyn, Inc., 111 Elwyn Road, Elwyn, Pennsylvania
| | - Lawrence Nelson
- Integrative Reproductive Medicine Unit, Intramural Research Program on Reproductive and Adult Endocrinology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, and Biochemistry, RUSH University Medical Center, Chicago, IL
| | - Jim Grigsby
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Denver, CO
| | - Paul J. Hagerman
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, CA
| | - Randi J. Hagerman
- M.I.N.D. Institute, University of California, Davis Medical Center, Sacramento, CA., Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA
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Abstract
The past decade has seen tremendous advances in our understanding of the molecular and genetic basis of many neuropsychiatric disorders. Although the genetic aberrations that lead to these syndromes have been identified in many cases, not much is known about specific gene products and their function. This article reviews the molecular basis of well-known neurogenetic disorders. The syndromes discussed here follow a Mendelian pattern of inheritance and are predominantly single-gene disorders; however, most childhood and adolescent psychiatric disorders are polygenic in nature. This genetic complexity and heterogeneity has made it difficult to identify the genes involved in their etiology. Identification of genetic and environmental risk factors involved in the etiology of complex disorders, such as autism, will help in the discovery of medications that can ameliorate the symptoms.
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Vulliemoz S, Dahoun S, Seeck M. Bilateral temporal lobe epilepsy in a patient with Turner syndrome mosaicism. Seizure 2007; 16:261-5. [PMID: 17182261 DOI: 10.1016/j.seizure.2006.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Revised: 11/06/2006] [Accepted: 11/13/2006] [Indexed: 10/23/2022] Open
Abstract
Turner's syndrome (TS), resulting from deletion of one X chromosome in women, is associated with cerebral development abnormalities, particularly in the temporal lobes. Symptomatic epilepsy is described only in cases with extensive malformations. Here, we report the first case of bilateral temporal epilepsy without macroscopic cerebral malformation in a woman with TS mosaicism. Bitemporal dysfunction was confirmed by the ictal and interictal EEG, PET, MR-spectroscopy and the neuropsychological examination, other causes than TS mosaicism were excluded. In rare cases, TS mosaicism may underlie non-lesional temporal lobe epilepsy, probably in relation to microanatomic structural and functional cerebral abnormalities. Further studies are needed to determine the frequency of this association.
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Affiliation(s)
- S Vulliemoz
- Department of Neurology, University Hospital of Geneva, Switzerland.
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Grigsby J, Leehey MA, Jacquemont S, Brunberg JA, Hagerman RJ, Wilson R, Epstein JH, Greco CM, Tassone F, Hagerman PJ. Cognitive Impairment in a 65-year-old Male With the Fragile X-associated Tremor-Ataxia Syndrome (FXTAS). Cogn Behav Neurol 2006; 19:165-71. [PMID: 16957495 DOI: 10.1097/01.wnn.0000213906.57148.01] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This is the first case report of a comprehensive neuropsychologic examination of an older man with the fragile X-associated tremor-ataxia syndrome (FXTAS). BACKGROUND FXTAS, a newly identified phenotype affecting older male carriers of the fragile X premutation allele, is a progressive disorder marked by gait ataxia, action tremor, peripheral neuropathy, executive cognitive deficits, generalized brain atrophy, and neuronal and astrocytic intranuclear inclusion bodies throughout the brain. The patient previously had undergone neurologic evaluation, molecular analysis, and magnetic resonance imaging. METHOD The patient was administered a neuropsychologic examination, assessing motor and somatosensory functioning, visual and spatial functioning, speech and language, attention, executive abilities, learning and memory, and reasoning. RESULTS The patient showed a pattern of cognitive impairment characterized by essentially normal speech and language, moderately impaired control of attention, and moderate to severe deficits in working memory, executive functioning, and both declarative and procedural learning. Visual and spatial abilities were relatively unimpaired, and verbal reasoning was only mildly deficient. CONCLUSIONS The findings suggest that a cognitive disorder, with especially marked executive cognitive function and memory deficits, accompanies FXTAS. The findings in FXTAS are compared with those in several other neurodegenerative disorders.
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Affiliation(s)
- Jim Grigsby
- Department of Medicine, University of Colorado Health Sciences Center, Aurora, CO 80045-5701, USA.
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Loesch DZ, Litewka L, Brotchie P, Huggins RM, Tassone F, Cook M. Magnetic resonance imaging study in older fragile X premutation male carriers. Ann Neurol 2005; 58:326-30. [PMID: 16049924 DOI: 10.1002/ana.20542] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Some carriers of a "premutation" allele of the FMR1 gene develop late-onset tremor/ataxia. We conducted a magnetic resonance imaging volumetric study in an unselected sample of eight older male premutation carriers. Volumetric measures, including total brain volume, and the volumes of cerebrum, cerebellum, and cerebral cortex all were significantly reduced in premutation carriers compared with similar data from 21 age-matched normal controls. Total brain and cerebral volumes were significantly related to the number of CGG repeats in the FMR1 gene. Moreover, increased hippocampal volume indicates this premutation may account for both neurodegenerative and neurodevelopmental changes.
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Affiliation(s)
- Danuta Z Loesch
- School of Psychological Science, La Trobe University, Bundoora, Victoria, Australia.
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Moore CJ, Daly EM, Schmitz N, Tassone F, Tysoe C, Hagerman RJ, Hagerman PJ, Morris RG, Murphy KC, Murphy DGM. A neuropsychological investigation of male premutation carriers of fragile X syndrome. Neuropsychologia 2004; 42:1934-47. [PMID: 15381024 DOI: 10.1016/j.neuropsychologia.2004.05.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Revised: 05/10/2004] [Accepted: 05/11/2004] [Indexed: 11/18/2022]
Abstract
It is currently thought that fragile X syndrome (FraX; the most common inherited form of learning disability) results from having more than 200 cytosine-guanine-guanine (CGG) trinucleotide repeats, with consequent methylation of the fragile X mental retardation (FMR1) gene and loss of FMR1 protein (FMRP). It was also considered that premutation carriers (with 55-200 CGG repeats) are unaffected, although a tremor/ataxia syndrome has recently been described in older adult male carriers. We reported that premutation expansion of CGG trinucleotide repeats affects brain anatomy, which, together with other studies, indicates that the molecular model for FraX needs modification. However, there are few studies on the cognitive ability of adult male premutation carriers. Thus, we selected 20 male premutation carriers on the basis of their genetic phenotype, and compared them to 20 male controls matched on age, IQ and handedness. We investigated intellectual functioning, executive function, memory, attention, visual and spatial perception, and language and pragmatics. The premutation carriers had significant impairments on tests of executive function (Verbal Fluency, Trail Making Test and Tower of London) and memory (Names sub-test of the Doors and People, Verbal Paired Associates Immediate Recall and Visual Paired Associates Delayed Recall sub-tests of the WMS-R, and Category Fluency Test for natural kinds). We therefore suggest that CGG trinucleotide repeats in the premutation range affect specific neuronal circuits that are concordant with specific neuropsychological deficits; and that these deficits reflect an emerging neuropsychological phenotype of premutation FraX.
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Affiliation(s)
- Caroline J Moore
- Division of Psychological Medicine, Section of Brain Maturation, Institute of Psychiatry, King's College London, DeCrespigny Park, London, UK.
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Steyaert J, Legius E, Borghgraef M, Fryns JP. A distinct neurocognitive phenotype in female fragile-X premutation carriers assessed with visual attention tasks. Am J Med Genet A 2003; 116A:44-51. [PMID: 12476450 DOI: 10.1002/ajmg.a.10821] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Premature ovarian failure (POF) and underlying hormonal changes are recognized as a distinct phenotype in female fragile-X premutation carriers. Neurocognitive deficits, in particular mental retardation, are associated with the full mutation in males and females. In female full mutation carriers this neurocognitive phenotype is expressed more mildly than in males. Research on whether the fragile-X premutation is associated with a particular neurocognitive phenotype or not has been equivocal. By means of the Sonneville Visual Attentions Tasks (SVAT) computer-based battery of neurocognitive tasks, we assessed reaction time on different tasks in three groups of subjects: female premutation carriers, female full mutation carriers, and female control subjects. The results show that a fraction of the female premutation carriers perform poorly on several selective attention tasks, but not on other tasks. Their neurocognitive profile is different from that of control subjects and of the majority of female premutation carriers. It may also be different from the phenotype of female full mutation carriers, though in that respect this study remains inconclusive. These findings support earlier findings that the fragile-X premutation may affect neurocognitive functioning, in particular aspects of attention.
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Affiliation(s)
- Jean Steyaert
- Department of Clinical Genetics, University of Maastricht, The Netherlands
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Kates WR, Folley BS, Lanham DC, Capone GT, Kaufmann WE. Cerebral growth in Fragile X syndrome: review and comparison with Down syndrome. Microsc Res Tech 2002; 57:159-67. [PMID: 12112452 DOI: 10.1002/jemt.10068] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neuroimaging studies have shown selective changes in brain size in Fragile X syndrome (FraX), which include reductions in the posterior cerebellar vermis, age-dependent increases in hippocampal volume, and enlarged caudate nucleus and thalamus. Contrasting with these limbic and subcortical anomalies, much less is known about the neocortex in FraX. The present study attempted to examine cerebral and lobar-level volumetric changes in young males with FraX (2-7 years), by comparing groups of subjects with full mutation (FM) and mosaicism (Mos) with both age-matched controls and subjects with developmental language delay (DLD) and Down syndrome (DS). For this purpose, we used high resolution (i.e, SPGR) MRI scans and semi-automated methods for segmenting (tissue class) and parcellating (i.e., Talairach) the brain. In agreement with previous studies, we found no changes in overall brain or cerebrum size in FraX. Nevertheless, boys with FM FraX had relative reductions in temporal lobe volume (primarily gray matter) and relative preservation/enlargement of parietal white matter volume. While temporal lobe reductions were not specific, since they were also observed in DLD and DS subjects, parietal preservation/enlargement was only seen in FraX. The relevance of these preliminary findings was emphasized by comparisons between FraX groups, which revealed more marked changes in FM FraX than in Mos FraX (i.e., gene dosage). While cross-sectional analyses revealed marked age-dependent decreases in DS, a group showing marked global and lobar volumetric reductions, there were no changes over time in FraX. These neuroimaging data are discussed in the context of FraX neurobiology and other developmental disorders.
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Affiliation(s)
- Wendy R Kates
- aMRI Analysis Laboratory, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
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Affiliation(s)
- R J Hagerman
- M.I.N.D. Institute and Department of Pediatrics, University of California at Davis Medical Center, Sacramento, California 95817, USA.
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Levitas A. Fragile X syndrome. J Am Acad Child Adolesc Psychiatry 2000; 39:398-9. [PMID: 10761338 DOI: 10.1097/00004583-200004000-00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Tassone F, Hagerman RJ, Taylor AK, Mills JB, Harris SW, Gane LW, Hagerman PJ. Clinical involvement and protein expression in individuals with the FMR1 premutation. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 91:144-52. [PMID: 10748416 DOI: 10.1002/(sici)1096-8628(20000313)91:2<144::aid-ajmg14>3.0.co;2-v] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most individuals with the fragile X premutation are clinically unaffected; however, some show clinical manifestations, including learning difficulties, emotional problems, or even mental retardation. The basis of clinical involvement in these individuals is unknown. Premutation alleles are reportedly associated with normal levels of mRNA and protein (FMRP). To examine this issue in more detail, we studied six individuals with a premutation. We are reporting these cases to demonstrate a spectrum of phenotypic involvement which can be seen clinically. These cases include one individual with the premutation who has no evidence of FMR1 gene dysfunction but has mental retardation from other causes. Other cases presented here show varying degrees of FMR1 gene dysfunction as assessed by FMRP and FMR1 mRNA levels and various clinical features of fragile X. In two cases we observed a significant reduction in FMRP expression and an elevated FMR1 mRNA expression level associated with moderate cognitive deficit. Thus, the utilization of FMRP measures can be helpful in understanding for which premutation patients clinical involvement is caused by dysfunction of the FMR1 gene.
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Affiliation(s)
- F Tassone
- Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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