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Leontiadis LJ, Trompoukis G, Felemegkas P, Tsotsokou G, Miliou A, Papatheodoropoulos C. Increased Inhibition May Contribute to Maintaining Normal Network Function in the Ventral Hippocampus of a Fmr1-Targeted Transgenic Rat Model of Fragile X Syndrome. Brain Sci 2023; 13:1598. [PMID: 38002556 PMCID: PMC10669536 DOI: 10.3390/brainsci13111598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
A common neurobiological mechanism in several neurodevelopmental disorders, including fragile X syndrome (FXS), is alterations in the balance between excitation and inhibition in the brain. It is thought that in the hippocampus, as in other brain regions, FXS is associated with increased excitability and reduced inhibition. However, it is still not known whether these changes apply to both the dorsal and ventral hippocampus, which appear to be differently involved in neurodegenerative disorders. Using a Fmr1 knock-out (KO) rat model of FXS, we found increased neuronal excitability in both the dorsal and ventral KO hippocampus and increased excitatory synaptic transmission in the dorsal hippocampus. Interestingly, synaptic inhibition is significantly increased in the ventral but not the dorsal KO hippocampus. Furthermore, the ventral KO hippocampus displays increased expression of the α1GABAA receptor subtype and a remarkably reduced rate of epileptiform discharges induced by magnesium-free medium. In contrast, the dorsal KO hippocampus displays an increased rate of epileptiform discharges and similar expression of α1GABAA receptors compared with the dorsal WT hippocampus. Blockade of α5GABAA receptors by L-655,708 did not affect epileptiform discharges in any genotype or hippocampal segment, and the expression of α5GABAA receptors did not differ between WT and KO hippocampus. These results suggest that the increased excitability of the dorsal KO hippocampus contributes to its heightened tendency to epileptiform discharges, while the increased phasic inhibition in the Fmr1-KO ventral hippocampus may represent a homeostatic mechanism that compensates for the increased excitability reducing its vulnerability to epileptic activity.
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Affiliation(s)
| | | | | | | | | | - Costas Papatheodoropoulos
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, 26504 Rion, Greece; (L.J.L.); (G.T. (George Trompoukis)); (P.F.); (G.T. (Giota Tsotsokou)); (A.M.)
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McCullagh EA, Rotschafer SE, Auerbach BD, Klug A, Kaczmarek LK, Cramer KS, Kulesza RJ, Razak KA, Lovelace JW, Lu Y, Koch U, Wang Y. Mechanisms underlying auditory processing deficits in Fragile X syndrome. FASEB J 2020; 34:3501-3518. [PMID: 32039504 DOI: 10.1096/fj.201902435r] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/31/2019] [Accepted: 01/18/2020] [Indexed: 01/14/2023]
Abstract
Autism spectrum disorders (ASD) are strongly associated with auditory hypersensitivity or hyperacusis (difficulty tolerating sounds). Fragile X syndrome (FXS), the most common monogenetic cause of ASD, has emerged as a powerful gateway for exploring underlying mechanisms of hyperacusis and auditory dysfunction in ASD. This review discusses examples of disruption of the auditory pathways in FXS at molecular, synaptic, and circuit levels in animal models as well as in FXS individuals. These examples highlight the involvement of multiple mechanisms, from aberrant synaptic development and ion channel deregulation of auditory brainstem circuits, to impaired neuronal plasticity and network hyperexcitability in the auditory cortex. Though a relatively new area of research, recent discoveries have increased interest in auditory dysfunction and mechanisms underlying hyperacusis in this disorder. This rapidly growing body of data has yielded novel research directions addressing critical questions regarding the timing and possible outcomes of human therapies for auditory dysfunction in ASD.
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Affiliation(s)
- Elizabeth A McCullagh
- Department of Physiology and Biophysics, University of Colorado Anschutz, Aurora, CO, USA.,Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
| | - Sarah E Rotschafer
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA.,Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA, USA
| | - Benjamin D Auerbach
- Center for Hearing and Deafness, Department of Communicative Disorders & Sciences, SUNY at Buffalo, Buffalo, NY, USA
| | - Achim Klug
- Department of Physiology and Biophysics, University of Colorado Anschutz, Aurora, CO, USA
| | - Leonard K Kaczmarek
- Departments of Pharmacology and Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Karina S Cramer
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - Randy J Kulesza
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, Erie, PA, USA
| | - Khaleel A Razak
- Department of Psychology, University of California, Riverside, CA, USA
| | | | - Yong Lu
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Ursula Koch
- Institute of Biology, Neurophysiology, Freie Universität Berlin, Berlin, Germany
| | - Yuan Wang
- Department of Biomedical Sciences, Program in Neuroscience, Florida State University, Tallahassee, FL, USA
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3
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Scharkowski F, Frotscher M, Lutz D, Korte M, Michaelsen-Preusse K. Altered Connectivity and Synapse Maturation of the Hippocampal Mossy Fiber Pathway in a Mouse Model of the Fragile X Syndrome. Cereb Cortex 2017; 28:852-867. [DOI: 10.1093/cercor/bhw408] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/22/2016] [Indexed: 12/12/2022] Open
Affiliation(s)
- F Scharkowski
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany
| | - Michael Frotscher
- ZMNH, Institute for Structural Neurobiology, D-20251 Hamburg, Germany
| | - David Lutz
- ZMNH, Institute for Structural Neurobiology, D-20251 Hamburg, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany
- Helmholtz Centre for Infection Research, AG NIND, 38124 Braunschweig, Germany
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Wang Y, Sakano H, Beebe K, Brown MR, de Laat R, Bothwell M, Kulesza RJ, Rubel EW. Intense and specialized dendritic localization of the fragile X mental retardation protein in binaural brainstem neurons: a comparative study in the alligator, chicken, gerbil, and human. J Comp Neurol 2015; 522:2107-28. [PMID: 24318628 DOI: 10.1002/cne.23520] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 11/09/2022]
Abstract
Neuronal dendrites are structurally and functionally dynamic in response to changes in afferent activity. The fragile X mental retardation protein (FMRP) is an mRNA binding protein that regulates activity-dependent protein synthesis and morphological dynamics of dendrites. Loss and abnormal expression of FMRP occur in fragile X syndrome (FXS) and some forms of autism spectrum disorders. To provide further understanding of how FMRP signaling regulates dendritic dynamics, we examined dendritic expression and localization of FMRP in the reptilian and avian nucleus laminaris (NL) and its mammalian analogue, the medial superior olive (MSO), in rodents and humans. NL/MSO neurons are specialized for temporal processing of low-frequency sounds for binaural hearing, which is impaired in FXS. Protein BLAST analyses first demonstrate that the FMRP amino acid sequences in the alligator and chicken are highly similar to human FMRP with identical mRNA-binding and phosphorylation sites, suggesting that FMRP functions similarly across vertebrates. Immunocytochemistry further reveals that NL/MSO neurons have very high levels of dendritic FMRP in low-frequency hearing vertebrates including alligator, chicken, gerbil, and human. Remarkably, dendritic FMRP in NL/MSO neurons often accumulates at branch points and enlarged distal tips, loci known to be critical for branch-specific dendritic arbor dynamics. These observations support an important role for FMRP in regulating dendritic properties of binaural neurons that are essential for low-frequency sound localization and auditory scene segregation, and support the relevance of studying this regulation in nonhuman vertebrates that use low frequencies in order to further understand human auditory processing disorders.
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Affiliation(s)
- Yuan Wang
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle, WA, 98195-7923
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Kidd SA, Lachiewicz A, Barbouth D, Blitz RK, Delahunty C, McBrien D, Visootsak J, Berry-Kravis E. Fragile X syndrome: a review of associated medical problems. Pediatrics 2014; 134:995-1005. [PMID: 25287458 DOI: 10.1542/peds.2013-4301] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common known genetic cause of inherited intellectual disability and the most common known single-gene cause of autism spectrum disorder. It has been reported that a spectrum of medical problems are commonly experienced by people with FXS, such as otitis media, seizures, and gastrointestinal problems. Previous studies examining the prevalence of medical problems related to FXS have been challenging to interpret because of their marked differences in population, setting, and sampling. Through this comprehensive review, we update the literature by reviewing studies that have reported on prominent medical problems associated with FXS. We then compare prevalence results from those studies with results from a large cross-sectional database consisting of data collected by fragile X clinics that specialize in the care of children with FXS and are part of the Fragile X Clinical and Research Consortium. It is vital for pediatricians and other clinicians to be familiar with the medical problems related to FXS so that affected patients may receive proper diagnosis and treatment; improved care may lead to better quality of life for these patients and their families.
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Affiliation(s)
- Sharon A Kidd
- National Fragile X Foundation, Walnut Creek, California;
| | - Ave Lachiewicz
- Departments of Pediatrics, Psychiatry, and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Deborah Barbouth
- Department of Human Genetics, University of Miami Miller School of Medicine, Miami, Florida
| | - Robin K Blitz
- Developmental Pediatrics, Barrow Neurologic Institute at Phoenix Children's Hospital, Phoenix, Arizona; Department of Pediatrics, University of Arizona College of Medicine, Phoenix, Arizona
| | - Carol Delahunty
- Department of Developmental and Rehabilitation Pediatrics, Cleveland Clinic, Cleveland, Ohio
| | - Dianne McBrien
- Department of Pediatrics, University of Iowa Medical Center, Iowa City, Iowa
| | - Jeannie Visootsak
- Departments of Human Genetics, and Pediatrics, Emory University, Atlanta, Georgia; and
| | - Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurologic Sciences, and Biochemistry, Rush University Medical Center, Chicago, Illinois
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Sun W, Wagnon JL, Mahaffey CL, Briese M, Ule J, Frankel WN. Aberrant sodium channel activity in the complex seizure disorder of Celf4 mutant mice. J Physiol 2012; 591:241-55. [PMID: 23090952 DOI: 10.1113/jphysiol.2012.240168] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mice deficient for CELF4, a neuronal RNA-binding protein, have a complex seizure disorder that includes both convulsive and non-convulsive seizures, and is dependent upon Celf4 gene dosage and mouse strain background. It was previously shown that Celf4 is expressed predominantly in excitatory neurons, and that deficiency results in abnormal excitatory synaptic neurotransmission. To examine the physiological and molecular basis of this, we studied Celf4-deficient neurons in brain slices. Assessment of intrinsic properties of layer V cortical pyramidal neurons showed that neurons from mutant heterozygotes and homozygotes have a lower action potential (AP) initiation threshold and a larger AP gain when compared with wild-type neurons. Celf4 mutant neurons also demonstrate an increase in persistent sodium current (I(NaP)) and a hyperpolarizing shift in the voltage dependence of activation. As part of a related study, we find that CELF4 directly binds Scn8a mRNA, encoding sodium channel Na(v)1.6, the primary instigator of AP at the axon initial segment (AIS) and the main carrier of I(NaP). In the present study we find that CELF4 deficiency results in a dramatic elevation in the expression of Na(v)1.6 protein at the AIS in both null and heterozygous neurons. Together these results suggest that activation of Na(v)1.6 plays a crucial role in seizure generation in this complex model of neurological disease.
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Affiliation(s)
- Wenzhi Sun
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609-1500, USA
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Friefeld SJ, Macgregor D. Sensorimotor coordination in boys with fragile X syndrome. Occup Ther Int 2012. [DOI: 10.1002/oti.6150010305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Wagnon JL, Mahaffey CL, Sun W, Yang Y, Chao HT, Frankel WN. Etiology of a genetically complex seizure disorder in Celf4 mutant mice. Genes Brain Behav 2011; 10:765-77. [PMID: 21745337 DOI: 10.1111/j.1601-183x.2011.00717.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mice deficient for the gene encoding the RNA-binding protein CELF4 (CUGBP, ELAV-like family member 4) have a complex seizure phenotype that includes both convulsive and non-convulsive seizures, depending upon gene dosage and strain background, modeling genetically complex epilepsy. Invertebrate CELF is associated with translational control in fruit fly ovary epithelium and with neurogenesis and neuronal function in the nematode. Mammalian CELF4 is expressed widely during early development, but is restricted to the central nervous system in adults. To better understand the etiology of the seizure disorder of Celf4 deficient mice, we studied seizure incidence with spatial and temporal conditional knockout Celf4 alleles. For convulsive seizure phenotypes, it is sufficient to delete Celf4 in adulthood at the age of 7 weeks. This timing is in contrast to absence-like non-convulsive seizures, which require deletion before the end of the first postnatal week. Interestingly, selective deletion of Celf4 from cerebral cortex and hippocampus excitatory neurons, but not from inhibitory neurons, is sufficient to lower seizure threshold and to promote spontaneous convulsions. Correspondingly, Celf4 deficient mice have altered excitatory, but not inhibitory, neurotransmission as measured by patch-clamp recordings of cortical layer V pyramidal neurons. Finally, immunostaining in conjunction with an inhibitory neuron-specific reporter shows that CELF4 is expressed predominantly in excitatory neurons. Our results suggest that CELF4 plays a specific role in regulating excitatory neurotransmission. We posit that altered excitatory neurotransmission resulting from Celf4 deficiency underlies the complex seizure disorder in Celf4 mutant mice.
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Affiliation(s)
- J L Wagnon
- The Jackson Laboratory, Bar Harbor, ME 04609-1500, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Abstract
The fragile X (FRAXA) mutation is typically manifested as either a full mutation (FM) or premutation (PM), and is often associated with some form of learning impairment. The study by Lachiewicz et al. in this issue suggests that females with the FM or PM exhibit a specific profile of strengths in verbal abilities and significant weaknesses in quantitative skills. We examined 17 females with either the FM or PM using a standard cognitive-behavioral battery consisting of the Stanford-Binet (4th Edition; SBFE) and the Vineland Adaptive Behavior Scale (VABS). Although we found the expected differences in composite IQ scores and adaptive behavior composite scores (DQ) between FM and PM females, we found no significant differences between verbal and quantitative reasoning in either group.
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Affiliation(s)
- Gene S Fisch
- Yeshiva University, New York, New York 10031, USA.
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11
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Abstract
The mental retardation protein FMRP is involved in the transport of mRNAs and their translation at synapses. Patients with fragile X syndrome, in whom FMRP is absent or mutated, show deficits in learning and memory that might reflect impairments in the translational regulation of a subset of neuronal mRNAs. The study of FMRP provides important insights into the regulation and functions of local protein synthesis in the neuronal periphery, and increases our understanding of how these functions can produce specific effects at individual synapses.
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Affiliation(s)
- Claudia Bagni
- Dipartimento di Biologia, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma, Italy.
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Liu W, Seto J, Sibille E, Toth M. The RNA binding domain of Jerky consists of tandemly arranged helix-turn-helix/homeodomain-like motifs and binds specific sets of mRNAs. Mol Cell Biol 2003; 23:4083-93. [PMID: 12773553 PMCID: PMC156124 DOI: 10.1128/mcb.23.12.4083-4093.2003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A deficit in the Jerky protein in mice causes recurrent seizures reminiscent of temporal lobe epilepsy. Jerky is present in mRNA particles in neurons. We show that the N-terminal 168 amino acids of Jerky are necessary and sufficient for mRNA binding. The binding domain is similar to the two tandemly arranged homeodomain-like helix-turn-helix DNA binding motifs of centromere binding protein B. The putative helix-turn-helix motifs of Jerky can also bind double-stranded DNA and represent a novel mammalian RNA/DNA binding domain. Microarray analysis identified mRNAs encoding proteins involved in ribosome assembly and cellular stress response that specifically bound to the RNA binding domain of Jerky both in vitro and in vivo. These data suggest that epileptogenesis in Jerky-deficient mice most likely involves pathways associated with ribosome biogenesis and neuronal survival and/or apoptosis.
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Affiliation(s)
- Wencheng Liu
- Department of Pharmacology, Weill Medical College of Cornell University. Graduate Program in Neuroscience, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10021, USA
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Abstract
PURPOSE We analyzed databases on chromosomal anomalies and epilepsy to identify chromosomal regions where abnormalities are associated with clinically recognizable epilepsy syndromes. The expectation was that these regions could then be offered as targets in the search for epilepsy genes. METHODS The cytogenetic program of the Oxford Medical Database, and the PubMed database were used to identify chromosomal aberrations associated with seizures and/or EEG abnormalities. The literature on selected small anomalies thus identified was reviewed from a clinical and electroencephalographic viewpoint, to classify the seizures and syndromes according to the current International League Against Epilepsy (ILAE) classification. RESULTS There were 400 different chromosomal imbalances described with seizures or EEG abnormalities. Eight chromosomal disorders had a high association with epilepsy. These comprised: the Wolf-Hirschhorn (4p-) syndrome, Miller-Dieker syndrome (del 17p13.3), Angelman syndrome (del 15q11-q13), the inversion duplication 15 syndrome, terminal deletions of chromosome 1q and 1p, and ring chromosomes 14 and 20. Many other segments had a weaker association with seizures. The poor quality of description of the epileptology in many reports thwarted an attempt to make precise karyotype-phenotype correlations. CONCLUSIONS We identified certain chromosomal regions where aberrations had an evident association with seizures, and these regions may be useful targets for gene hunters. New correlations with specific epilepsy syndromes were not revealed. Clinicians should continue to search for small chromosomal abnormalities associated with specific epilepsy syndromes that could provide important clues for finding epilepsy genes, and the epileptology should be rigorously characterized.
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Affiliation(s)
- Rita Singh
- Department of Medicine (Neurology), The University of Melbourne, Austin and Repatriation Medical Centre, Australia
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Abstract
Fragile X syndrome is the most prevalent cause of mental retardation. It is usually caused by the transcriptional inactivation of the FMR-1 gene. Although the cognitive defect is the most recognized symptom of fragile X syndrome, patients also show behavioral problems such as hyperarousal, hyperactivity, autism, aggression, anxiety and increased sensitivity to sensory stimuli. Here we investigated whether fragile X mice (fmr-1 gene knockout mice) exhibit abnormal sensitivity to sensory stimuli. First, hyperreactivity of fragile X mice to auditory stimulus was indicated in the prepulse inhibition paradigm. A moderately intense prepulse tone, that suppresses startle response to a strong auditory stimulus, elicited a significantly stronger effect in fragile X than in control mice. Second, sensory hyperreactivity of fragile X mice was demonstrated by a high seizure susceptibility to auditory stimulation. Selective induction of c-Fos, an early-immediate gene product, indicated that seizures involve auditory brainstem and thalamic nuclei. Audiogenic seizures were not due to a general increase in brain excitability because three different chemical convulsants (kainic acid, bicuculline and pentylenetetrazole) elicited similar effects in fragile X and wild-type mice. These data are consistent with the increased responsiveness of fragile X patients to auditory stimuli. The auditory hypersensitivity suggests an abnormal processing in the auditory system of fragile X mice, which could provide a useful model to study the molecular and cellular changes underlying fragile X syndrome.
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Affiliation(s)
- L Chen
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, LC 522, New York, NY 10021, USA
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Abstract
Of the 24 males identified as having fragile X syndrome in the Northeast Essex screening programme, 25% had epilepsy. Epilepsy in individuals with fragile X syndrome is known to follow a benign course with seizures disappearing before the age of 20. However, half of our sample with a history of epilepsy continued to have seizures after the age of 20. We reviewed the EEG reports of 18 of the 24 individuals (aged between 13 and 63 years) including all six individuals with epilepsy. We had 32 EEG recordings from 18 subjects, with nine people having more than one recording at different points. The EEG showed a definite improvement in only five individuals. Three individuals who had serial recordings (one with epilepsy) showed no significant changes over time and the EEG of one subject with epilepsy deteriorated. The most common abnormal EEG findings were rhythmic theta activity (50%) and a slowing of background activity (28%). There were no characteristic features in the sleep EEGs performed on four subjects. The possible implications of these preliminary findings are discussed.
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Affiliation(s)
- M Sabaratnam
- Imperial College, London, and Ealing Community Team for People with Learning Disabilities, 62 Green Lane, Hanwell, London, W7 2PB, UK.
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Abstract
Progress in understanding the genetics of epilepsy is proceeding at a dizzying pace. Due in large part to rapid progress in molecular genetics, gene defects underlying many of the inherited epilepsies have been mapped, and several more are likely to be added each year. In this review, we summarize the available information on the genetic basis of human epilepsies and epilepsy syndromes, and correlate these advances with rapidly expanding information about the mechanisms of epilepsy gained from both spontaneous and transgenic animal models. We also provide practical suggestions for clinicians confronted with families in which multiple members are afflicted with epilepsy.
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Affiliation(s)
- A N Prasad
- Department of Pediatrics, The Charles A. Janeway Child Health Centre, St. John's, Newfoundland, Canada
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Affiliation(s)
- W E Kaufmann
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Mazzocco MM, Pulsifer M, Fiumara A, Cocuzza M, Nigro F, Incorpora G, Barone R. Brief report: autistic behaviors among children with fragile X or Rett syndrome: implications for the classification of pervasive developmental disorder. J Autism Dev Disord 1998; 28:321-8. [PMID: 9711488 DOI: 10.1023/a:1026012703449] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- M M Mazzocco
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Guerreiro MM, Camargo EE, Kato M, Marques-de-Faria AP, Ciasca SM, Guerreiro CA, Netto JR, Moura-Ribeiro MV. Fragile X syndrome. Clinical, electroencephalographic and neuroimaging characteristics. Arq Neuropsiquiatr 1998; 56:18-23. [PMID: 9686115 DOI: 10.1590/s0004-282x1998000100003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We studied 11 patients (9 males) with cytogenetic diagnosis of fragile X syndrome (FXS) with the purpose of investigating the neural circuitry involved in this condition. The ages ranged from 8 to 19. All the individuals presented large ears, elongated faces and autistic features. Ten patients had severe mental retardation. Attention disorder was found in 10 individuals. Electroencephalographic recordings were abnormal in 6 of 10 patients examined, showing focal epileptiform discharges predominantly in frontal and parietal areas. All patients underwent magnetic resonance imaging studies which were abnormal in 8 of them. The most important abnormalities were reduction of the cerebellar vermis and enlargement of the IV ventricle. Single photon emission computerized tomography (SPECT) was performed in 7 patients and was abnormal in all of them, the most frequent finding being a hypoperfusion of the inferior of the frontal lobes. Based on the clinical picture, neuropsychological findings and functional and structural imaging studies we suggest that FXS presents with a dysfunction involving a large area of the central nervous system: cerebellum-basal frontal regions-parietal lobes. The literature points to a disturbance involving the same neural circuitry in patients with autism.
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Affiliation(s)
- M M Guerreiro
- Departamento de Neurologia, Faculdade de Ciências Médicas (FCM) da Universidade Estadual de Campinas (UNICAMP), Brasil
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20
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Abstract
Reports of autistic behaviors were examined for 30 school-age girls with fragile X (fraX) and 31 age- and IQ-matched controls through a structured interview administered to each girl's parent(s). IQ scores were obtained for each participant; anxiety, neuroanatomical, and molecular-genetic data were derived for girls with fraX. Girls with fraX had significantly more autistic behaviors than controls. These behaviors were qualitatively similar to those reported for boys with fraX, but were not correlated with IQ. Anxiety in girls with fraX was positively correlated with abnormal social and communication behaviors; posterior cerebellar vermis area was negatively correlated with measures of communication and stereotypic/restricted behaviors. Severity of stereotypic/restricted behaviors was negatively correlated with the prevalence of active non-fraX chromosomes. Thus anxiety and posterior cerebellar area measures had distinct associations with subsets of autistic behaviors; these associations may have important implications for understanding the neurobiology of autism.
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Affiliation(s)
- M M Mazzocco
- Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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21
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Previc FH. Nonright‐handedness, central nervous system and related pathology, and its lateralization: A reformulation and synthesis. Dev Neuropsychol 1996. [DOI: 10.1080/87565649609540663] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Franke P, Barbe B, Leboyer M, Maier W. Fragile X syndrome. II. Cognitive and behavioral correlates of mutations of the FMR-1 gene. Eur Psychiatry 1996; 11:233-43. [DOI: 10.1016/0924-9338(96)82329-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/1995] [Accepted: 05/21/1996] [Indexed: 10/17/2022] Open
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Schapiro MB, Murphy DG, Hagerman RJ, Azari NP, Alexander GE, Miezejeski CM, Hinton VJ, Horwitz B, Haxby JV, Kumar A. Adult fragile X syndrome: neuropsychology, brain anatomy, and metabolism. Am J Med Genet 1995; 60:480-93. [PMID: 8825884 DOI: 10.1002/ajmg.1320600603] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To understand the implications of suboptimal gene expression in fragile X syndrome -fra(X)-, we sought to define the central nervous abnormalities in fra(X) syndrome to determine if abnormalities in specific brain regions or networks might explain the cognitive and behavioral abnormalities in this syndrome. Cranial and ventricular volumes were measured with quantitative computed tomography (CT), regional cerebral metabolic rates for glucose (rCMRglc) were measured with [18-F]-2-fluoro-2-deoxy-D-glucose (18FDG), and patterns of cognition were determined with neuropsychological testing in ten healthy, male patients with karyotypically proven fra(X) syndrome (age range 20-30 yr). Controls for the CT studies were 20 healthy males (age range 21-37 yr), controls for the PET studies were 9 healthy males (age range 22-31 yr), and controls for the neuropsychological tests were 10 young adult, male Down syndrome (DS) subjects (age range 22-31 yr). The mean mental age of the fra(X) syndrome group was 5.3 yr (range 3.5-7.5 yr; Stanford-Binet Intelligence Scale). Despite comparable levels of mental retardation, the fra(X) subjects showed poorer attention/short term memory in comparison to the DS group. Further, the fra(X) subjects showed a relative strength in verbal compared to visuospatial attention/short term memory. As measured with quantitative CT, 8 fra(X) subjects had a significant (P < 0.05) 12% greater intracranial volume (1,410 +/- 86 cm3) as compared to controls (1,254 +/- 122 cm3). Volumes of the right and left lateral ventricles and the third ventricle did not differ between groups. Seven of eight patients had greater right lateral ventricle volumes than left, as opposed to 9 out of 20 controls (P < 0.05). Global gray matter CMR-glc in nine fra(X) patients was 9.79 +/- 1.28 mg/100 g/minute and did not differ from 8.84 +/- 1.31 mg/100 g/minute in the controls. R/L asymmetry in metabolism of the superior parietal lobe was significantly higher in the patients than controls. A preliminary principal component analysis of metabolic data showed that the fra(X) subjects tended to form a separate subgroup that is characterized by relative elevation of normalized metabolism in the lenticular nucleus, thalamus, and premotor regions. Further, a discriminant function, that reflected rCMRglc interactions of the right lenticular and left premotor regions, distinguished the fra(X) subjects from controls. These regions are part of a major group of functionally and anatomically related brain regions and appear disturbed as well in autism with which fra(X) has distinct behavioral similarities. These results show a cognitive profile in fra(X) syndrome that is distinct from that of Down syndrome, that the larger brains in fragile X syndrome are not accompanied by generalized cerebral cortical atrophy or hypoplasia, and that distinctive alterations in resting regional glucose metabolism, measured with 18 FDG and PET, occur in fra(X) syndrome.
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Affiliation(s)
- M B Schapiro
- Section on Brain Aging and Dementia, National Institute on Aging, Clinical Center, Bethesda, Maryland 20892, USA
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Abstract
A population-based study of active epilepsy in mentally retarded children identified 98 children, 6-13 years old. A biopathological origin was established in 66% of mildly and 92% of severely retarded children: a prenatal etiology was considered in 51% and 57%, a perinatal in 9% and 19%, a postnatal in 6% and 16% and an untraceable etiology in 34% and 8%, respectively. Severe mental retardation was more frequent in the peri- and postnatal groups (80% and 83%) than in the prenatal and untraceable groups (67% and 29%). Thirty-four pre- and perinatal optimal items were defined. Children with a prenatal etiology did not differ from controls in any of the periods. Children with a perinatal etiology had, compared with controls, higher proportions of non-optimal items successively increasing through the pre- and perinatal periods showing the accumulation of negative events.
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Affiliation(s)
- U Steffenburg
- Department of Pediatrics, University of Göteborg, Ostra Hospital, Sweden
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Schaap C, Fryns JP. Severe progressive neurological disorder associated with hydrocephalus in a man with fragile X syndrome. Am J Med Genet 1994; 51:403-4. [PMID: 7943007 DOI: 10.1002/ajmg.1320510420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Abstract
Karyotypic and DNA analyses were both performed on 104 autistic children referred from Taichung Autism Education Academy and Tainan Autism Association in Taiwan. The frequency of fragile sites of the autistic patients did not differ significantly from that of the normal individuals. Of the 12 autistic children with chromosomal abnormalities, 8 had the fragile X, 2 had Down syndrome, and the remaining had other aneuploid constitutions. The results of this study illustrate the contribution of chromosomal abnormalities or variants to the pathogenesis of infantile autism.
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Affiliation(s)
- S Y Li
- Cytogenetics Laboratory, Chung Shan Medical and Dental College, Taichung, Taiwan, Republic of China
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Abstract
A four-year retrospective survey of individuals referred for fragile X testing to South East Thames Regional Genetics Service was carried out to determine the accuracy of clinical diagnosis of fragile X syndrome among routine referrals for cytogenetic confirmation. 680 individuals from 565 pedigrees were tested for fragile X. Five affected males were identified in previously unknown families and 17 new pedigrees were diagnosed. Using the accepted prevalence data, a total of 80 affected males would have been expected in this period. The most likely explanation for the low diagnosis rate is failure of referral of affected males.
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Affiliation(s)
- A J Barnicoat
- Department of Medical and Molecular Genetics, United Medical School, Guy's Hospital, London
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Abstract
The patient was a 9-year-old boy. He began to walk at the age 1 year and 8 months and began to speak at the age of 2 years, suggesting retarded mental and motor development. A diagnosis of DMD was made when he was 7 years old. On admission, the patient exhibited a peculiar thin and long face, large auricles, narrow palate, malalignment of the teeth, epicanthus, saddle nose, and simian lines in addition to symptoms consistent with DMD. Chromosome analysis showed fragile X at Xq27 at a frequency of 20%. His mother also showed fragile X at the same position. Since the atypical features of this DMD patient are all explained as fragile X syndrome, this case was considered to be a very rare instance of DMD whose clinical pictures were modified by fragile X syndrome.
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Affiliation(s)
- W T Brown
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York
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Abstract
Fragile X [fraX] syndrome is a common hereditary disorder associated with a fragile site marker at Xq27.3 which clinically presents as a form of mental retardation (MR). Postmortem investigation of 3 fraX positive males with mild to moderate MR did not document any gross neuropathological changes. Golgi analysis of neocortical dendritic spine morphology extended our previous observations of immature, long, tortuous spines in one adult case of fraX (Rudelli, et al., Acta Neuropathologica 67:289-295, 1985) to 2 new cases. Evidence for similar dendritic spine abnormalities was found, although Golgi analysis was less than optimal because of incomplete dendritic stain impregnation. Neocortical intra-layer cell density was also investigated in all 3 cases. Cresyl violet stained neurons were counted in 10 randomly selected fields in neocortical layers II-VI of cingulate and temporal association areas (Brodmann's areas 23 and 38). Neuron counts in fraX and control neocortex showed no significant differences. Thus, abnormal dendritic spine morphology with preservation of neuronal density appears to characterize the neocortex in individuals with this common form of mental retardation.
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Affiliation(s)
- V J Hinton
- Queens College, City University of New York, New York
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Abstract
Pediatricians can identify a child with a developmental language disorder by expanding a traditional developmental assessment with special screening tests of language skills. They can direct parents to specialists who can define the nature of the language disturbance in more detail and predict its natural history. They must then support the parents as they learn to use the community resources available for remediation of their child. As more is learned about the biologic bases of normal and abnormal language development in children, pediatricians will undoubtedly have an even more central role in identification of patients with language disorders and education of their families.
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Affiliation(s)
- S K Klein
- Department of Pediatrics, Case Western Reserve University, Rainbow Babies and Childrens Hospital, Cleveland, Ohio
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Affiliation(s)
- L M Spano
- Department of Medical Genetics, Shodair Children's Hospital, Helena, Montana 59604
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Wisniewski KE, Segan SM, Miezejeski CM, Sersen EA, Rudelli RD. The Fra(X) syndrome: neurological, electrophysiological, and neuropathological abnormalities. Am J Med Genet 1991; 38:476-80. [PMID: 2018089 DOI: 10.1002/ajmg.1320380267] [Citation(s) in RCA: 195] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have evaluated 62 fragile X syndrome [fra(X)] individuals (55 males and 7 females) with different degrees of developmental disabilities that were clinically non-progressive and non-focal in character. The mean age for the 55 males was 23.1 years +/- 14.3 SD with a range of 2-70: for the 7 females, the mean age was 15.7 years +/- 3.5 SD with a range of 10-20 years. Mental retardation (MR) was found in 53 males (8/53 [15.1%] mild, 26/53 [49.1%] moderate, 14/53 [26.4%] severe, and 5/53 [9.4%] profound). Learning disabilities were found in 2/55 (3.6%) of males. One of the 7 females had mild and one had moderate MR: the other 5 were learning disabled. Autistic stigmata were present in 10/62 (16%) of the patients. Only 14/62 (23%) had a history of seizures, all of which were controlled with anticonvulsants. In 36/62 cases, an electroencephalogram (EEG) was performed. We compared these data with that of others. Brain stem auditory evoked response (BAER) was performed in 12 cases. Abnormalities were found in only 5/12. Neuroimaging and computerized cranial transaxial tomography (CT scan) were performed on 21/62 (34%) of the patients. Only 8 of these 21 (38%) studies were abnormal. One patient died; neuropathological studies showed mild brain atrophy, with light microscopic and ultrastructural abnormalities. Rapid Golgi dendritic spine patterns showed that the proximal apical segments were abnormally developed. Very thin, long tortuous spines with prominent terminal heads and irregular dilatations were present. Marked reductions in the length of the synapses, as determined on EPTA-postfixed tissue where noted.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K E Wisniewski
- New York State Office of Mental Retardation and Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island 10314
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Abstract
All mentally retarded (MR) subjects in a northern Swedish county were assessed for the occurrence of active epilepsy on a prevalence day. Active epilepsy was found in 299 subjects (20.2% of those with MR) corresponding to a crude prevalence rate of 1.2/1000 inhabitants. The age-specific prevalence for 0-9 years was higher for females than for males, while in other age groups it was slightly higher for males or showed no difference between the sexes. Epilepsy and MR were the only disorders in 129 subjects (43.1%). Cerebral palsy was the most common associated disorder and occurred in 100 (33.4%). A presumable etiology for epilepsy and MR was identified in 73.2% and 71.9%, respectively. The presumable etiological factors which caused MR occurred prenatally in 35%, perinatally in 10% and postnatally in 9%. The pathogenetic period was unknown in 31%. In 15%, the etiological events occurred during more than one of the above periods. The presumable causes were responsible for both epilepsy and MR in all except 7 cases. MR individuals with epilepsy were significantly more retarded than those without epilepsy. The first seizure occurred during the neonatal period in 11.6% and before 1 year of age in 27.7%. Generalized tonic-clonic seizures were the most common type and occurred in 204 subjects (68.2%). Seventy-one of these also had partial seizure manifestations. Daily to weekly seizures occurred in 26.8% and 32.0% had been seizure-free for the past year.
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Affiliation(s)
- L Forsgren
- Department of Neurology, Umeå University, University Hospital, Sweden
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Cohen IL, Brown WT, Jenkins EC, Krawczun MS, French JH, Raguthu S, Wolf-Schein EG, Sudhalter V, Fisch G, Wisniewski K. Fragile X syndrome in females with autism. Am J Med Genet 1989; 34:302-3. [PMID: 2817015 DOI: 10.1002/ajmg.1320340240] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Abstract
A clinical, neurological and electroencephalographic investigation was undertaken in 29 previously cytogenetically verified hemizygous males with the fra(X) form of mental retardation (age range 3.5 to 59 years); in addition, 6 heterozygous females were examined. All male patients displayed the known physical aspects of this syndrome together with associated abnormalities of the palate, skeleton, connective tissue and endocrine system. The most prominent neurological features were different forms of oculomotor disturbances, minor motor and pyramidal signs, incoordination, muscle hypotonia, gait and speech abnormalities. There was no increased frequency either in seizures or in epileptic EEG discharges. Some patients had a slowing of background activity in EEG. About 50% of all patients displayed autistic-like behaviour, short attention span and/or hyperactivity. In accordance with the literature, the findings indicate that there are no neurological, electroencephalographic or neuroradiological features which occur specifically in this syndrome. The need to differentiate the findings from those resulting from encephalopathic mechanisms during the gestational and perinatal period is stressed. A distinct typing of seizures and EEG changes is needed in each patient, before definite conclusions about an association of seizures and fra(X) syndrome are drawn. In view of the lack of correlation between IQ and the clinical-neurological measures, a more practical approach to quantifying the mental impairment is proposed.
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Affiliation(s)
- P Vieregge
- Klinik für Neurologie, Medizinische Universität zu Lübeck, Federal Republic of Germany
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Affiliation(s)
- L M Spano
- Department of Medical Genetics, Shodair Children's Specialty Hospital, Helena, Montana 59604
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Wisniewski KE, Rapin I, Heaney-Kieras J. Clinico-pathological variability in the childhood neuronal ceroid-lipofuscinoses and new observations on glycoprotein abnormalities. Am J Med Genet Suppl 1988; 5:27-46. [PMID: 3146325 DOI: 10.1002/ajmg.1320310607] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Our 86 cases of neuronal ceroid-lipofuscinosis (NCL) included 7 children with the infantile variant, 28 with the late infantile variant, and 51 with the juvenile variant. Thirty-one cases were drawn from a NCL registry and were not evaluated personally by the authors. Another 30 cases from the registry were not included because of inadequate data. The clinical course was subacute in most children with the infantile and late infantile variants and chronic in the juvenile variant. Sixteen of 86 cases (19%) were considered to be atypical clinically [3/7 (43%) with the infantile variant, 3/28 (11%) with the late infantile variant, and 10/51 (20%) with the juvenile variant]. Clinical variability among and between families was most striking in the juvenile variant. Pathological investigations of skin, buffy coat and/or brain showed atypical and/or more than one type of cytoplasmic inclusions in 10/50 (20%) of late infantile and juvenile variants. All of the children with the infantile variant had granular, osmiophilic profile in tissues. Biochemical studies on the glycoproteins of cultured fibroblasts in three cases of juvenile NCL showed that there was a higher proportion of one size class of N-linked oligosaccharides and a higher proportion of mannose-containing glycoproteins in NCL than in control cells. This supports previous lectin histochemical studies of glycoconjugates in skin of juvenile NCL [Wisniewski and Szumanska, 1986] and suggests that there may be defects in the processing of N-linked oligosaccharides in the glycoproteins of juvenile NCL.
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Affiliation(s)
- K E Wisniewski
- New York State Office of Mental Retardation and Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314
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Abstract
A clinical and EEG study of 12 fragile-X syndrome subjects (six with epilepsy) is presented. All subjects had clinical-family history examinations, EEG evaluations, and karyotyping. Spikes were present in the sleep EEG of one nonepileptic and four epileptic subjects: these spikes were similar in location, occurrence, voltage, frequency, and morphology (and similar to those of the Rolandic spikes). These data, together with the clinical similarities (type of epilepsy, responses to drugs, ages of seizure onset, etc.), have resulted in the postulation of EEG characteristics of epileptic and nonepileptic fragile-X patients. However, further studies with fragile-X patients are needed to confirm this hypothesis.
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Affiliation(s)
- S A Musumeci
- Oasi, Istituto di Ricerca sul Ritardo Mentale, Troina, Italy
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Brown WT, Jenkins EC, Krawczun MS, Wisniewski K, Rudelli R, Cohen IL, Fisch G, Wolf-Schein E, Miezejeski C, Dobkin C. The fragile X syndrome. Ann N Y Acad Sci 1986; 477:129-50. [PMID: 3545014 DOI: 10.1111/j.1749-6632.1986.tb40329.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Wisniewski KE. The diagnostic value of ultrastructural studies of skin-punch biopsies and buffy coat for the early diagnosis of some neurodegenerative diseases. Ann N Y Acad Sci 1986; 477:285-311. [PMID: 3028228 DOI: 10.1111/j.1749-6632.1986.tb40349.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
Genetic linkage between a factor IX DNA restriction fragment length polymorphism (RFLP) and the fragile X chromosome marker was analyzed in eight fragile X pedigrees and compared to eight previously reported pedigrees. A large pedigree with apparently full penetrance in all male members showed a high frequency of recombination. A lod score of -7.39 at theta = 0 and a maximum score of 0.26 at theta = 0.32 were calculated. A second large pedigree with a nonpenetrant male showed tight linkage with a maximum lod score of 3.13 at theta = 0, a result similar to one large pedigree with a nonpenetrant male previously reported. The differences in lod scores seen in these large pedigrees suggested there was genetic heterogeneity in linkage between families which appeared to relate to the presence of nonpenetrant males. The combined lod score for the three pedigrees with nonpenetrant males was 6.84 at theta = 0. For the 13 other pedigrees without nonpenetrant males the combined lod score was -21.81 at theta = 0, with a peak of 0.98 at theta = 0.28. When lod scores from all 16 families were combined, the value was -15.14 at theta = 0 and the overall maximum was 5.13 at theta = 0.17. To determine whether genetic heterogeneity was present, three statistical tests for heterogeneity were employed. First, a "predivided-sample" test was used. The 16 pedigrees were divided into two classes, NP and P, based upon whether or not any nonpenetrant males were detected in the pedigree. This test gave evidence for significant genetic heterogeneity whether the three large pedigrees with seven or more informative males (P less than 0.005), the eight pedigrees with three informative males (P less than 0.001), or all 16 pedigrees (P less than 0.001) were included in the analysis. Second, Morton's large sample test was employed. Significant heterogeneity was present when the analysis was restricted to the three large pedigrees (P less than 0.025), or to the eight pedigrees with informative males (P less than 0.05) but not when smaller, less informative pedigrees were also included. Third, an "admixture" test for heterogeneity was employed which tests for linkage versus no linkage. A trend toward significance was seen (0.05 less than P less than 0.10) which increased when the analysis was restricted to the larger, more informative pedigrees.(ABSTRACT TRUNCATED AT 400 WORDS)
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Rudelli RD, Brown WT, Wisniewski K, Jenkins EC, Laure-Kamionowska M, Connell F, Wisniewski HM. Adult fragile X syndrome. Clinico-neuropathologic findings. Acta Neuropathol 1985; 67:289-95. [PMID: 4050344 DOI: 10.1007/bf00687814] [Citation(s) in RCA: 285] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fragile X syndrome [fra (X)] is currently accepted as the second most frequent chromosomal disorder associated with developmental disability. Although next to Down syndrome in frequency, no postmortem studies of confirmed adult cases had been reported. The autopsy examination of a 62-year-old, moderately retarded man with the fra (X) syndrome confirmed the preferential involvement of cerebral and testicular structures in this disorder. Dendritic spine abnormalities of the type observed in trisomic chromosomal disorders were associated with synaptic immaturity. Severe testicular hypogonadism accompanied bilateral macro-orchidism, normal penis, and unilateral hydrocele. Valvular, articular, and testicular interstitial compartments showed normal histochemical staining characteristics for glycoproteins and lipids.
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