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Mahale R, Purushottam M, Singh R, Yelamanchi R, Kamble N, Holla V, Pal PK, Jain S, Yadav R. Revisiting Friedreich's Ataxia: Phenotypic and Imaging Characteristics. Ann Indian Acad Neurol 2024; 27:152-157. [PMID: 38751907 PMCID: PMC11093178 DOI: 10.4103/aian.aian_1001_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/07/2024] [Accepted: 03/10/2024] [Indexed: 05/18/2024] Open
Abstract
Background and Aim Friedreich's ataxia (FRDA) is a common cause of autosomal recessive cerebellar ataxia. The phenotype is dependent on the repeat size and duration of the disease. We aimed to study the clinical, electrophysiologic, and radiologic profiles in a large Indian cohort of genetically proven FRDA patients. Subjects and Methods A retrospective cross-sectional, descriptive analysis of genetically proven FRDA patients was performed. A detailed review of all the hospital case records was done to analyze the clinical, radiologic, and electrophysiologic details. Results A total of 100 FRDA patients were selected for the analysis. Eighty-six patients had an age at onset between 5 and 25 years. Eight patients (8%) were classified as late-onset FRDA and six patients (6%) as early-onset FRDA. The median age at presentation was 19 years. The median age at onset was 14 years, and the median duration of illness was 4 years. All patients had gait ataxia as the initial symptom. Gait ataxia, loss of proprioception, and areflexia were seen in all patients. Dysarthria, nystagmus, amyotrophy, spasticity, extensor plantars, pes cavus, and scoliosis occurred in one-third of patients. Cardiomyopathy (18%) and diabetes (5%) were less common. Sensory polyneuropathy (87.5%) was the most common nerve conduction abnormality. Cortical somatosensory evoked responses were absent in all 43 tested patients (100%). Brainstem auditory evoked response test was done in 24 patients and it showed absent reactions in six patients (25%). Visual evoked potential was tested in 24 patients and it showed absent P100 responses in five patients (21%). Cerebellar and cord atrophy was seen on magnetic resonance imaging in 50% of patients. Conclusion Most FRDA patients (86%) had an age at onset of less than 25 years, with typical symptoms of gait ataxia, areflexia, and loss of proprioception found in all patients. Dysarthria, nystagmus, amyotrophy, spasticity, extensor plantars, pes cavus, scoliosis, cardiomyopathy, and diabetes were not seen in all patients. Cerebellar atrophy can occur in FRDA patients. Knowledge regarding the clinical, radiologic, and electrophysiologic profile of FRDA will aid in proper phenotypic characterization.
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Affiliation(s)
- Rohan Mahale
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Meera Purushottam
- Molecular Genetics Lab, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Raviprakash Singh
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Ramachandra Yelamanchi
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Nitish Kamble
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Vikram Holla
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Pramod K. Pal
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Sanjeev Jain
- Molecular Genetics Lab, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
| | - Ravi Yadav
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India
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Krasilnikova MM, Humphries CL, Shinsky EM. Friedreich's ataxia: new insights. Emerg Top Life Sci 2023; 7:313-323. [PMID: 37698160 DOI: 10.1042/etls20230017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/09/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023]
Abstract
Friedreich ataxia (FRDA) is an inherited disease that is typically caused by GAA repeat expansion within the first intron of the FXN gene coding for frataxin. This results in the frataxin deficiency that affects mostly muscle, nervous, and cardiovascular systems with progressive worsening of the symptoms over the years. This review summarizes recent progress that was achieved in understanding of molecular mechanism of the disease over the last few years and latest treatment strategies focused on overcoming the frataxin deficiency.
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Affiliation(s)
- Maria M Krasilnikova
- Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, U.S.A
| | - Casey L Humphries
- Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, U.S.A
| | - Emily M Shinsky
- Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, U.S.A
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3
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Aguilera C, Esteve-Garcia A, Casasnovas C, Vélez-Santamaria V, Rausell L, Gargallo P, Garcia-Planells J, Alía P, Llecha N, Padró-Miquel A. Novel intragenic deletion within the FXN gene in a patient with typical phenotype of Friedreich ataxia: may be more prevalent than we think? BMC Med Genomics 2023; 16:312. [PMID: 38041144 PMCID: PMC10693098 DOI: 10.1186/s12920-023-01743-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 11/18/2023] [Indexed: 12/03/2023] Open
Abstract
BACKGROUND Friedreich ataxia is the most common inherited ataxia in Europe and is mainly caused by biallelic pathogenic expansions of the GAA trinucleotide repeat in intron 1 of the FXN gene that lead to a decrease in frataxin protein levels. Rarely, affected individuals carry either a large intragenic deletion or whole-gene deletion of FXN on one allele and a full-penetrance expanded GAA repeat on the other allele. CASE PRESENTATION We report here a patient that presented the typical clinical features of FRDA and genetic analysis of FXN intron 1 led to the assumption that the patient carried the common biallelic expansion. Subsequently, parental sample testing led to the identification of a novel intragenic deletion involving the 5'UTR upstream region and exons 1 and 2 of the FXN gene by MLPA. CONCLUSIONS With this case, we want to raise awareness about the potentially higher prevalence of intragenic deletions and underline the essential role of parental sample testing in providing accurate genetic counselling.
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Affiliation(s)
- Cinthia Aguilera
- Genetics Laboratory, Laboratori Clínic Territorial Metropolitana Sud. Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain.
| | - Anna Esteve-Garcia
- Clinical Genetics Unit, Laboratori Clínic Territorial Metropolitana Sud. Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Carlos Casasnovas
- Neuromuscular Unit, Neurology Department, Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
- Neurometabolic Diseases Group, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
- Biomedical Research Network Centre in Rare Diseases (CIBERER), Madrid, Spain
| | - Valentina Vélez-Santamaria
- Neuromuscular Unit, Neurology Department, Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
| | | | | | | | - Pedro Alía
- Genetics Laboratory, Laboratori Clínic Territorial Metropolitana Sud. Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Núria Llecha
- Genetics Laboratory, Laboratori Clínic Territorial Metropolitana Sud. Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
- Clinical Genetics Unit, Laboratori Clínic Territorial Metropolitana Sud. Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Ariadna Padró-Miquel
- Genetics Laboratory, Laboratori Clínic Territorial Metropolitana Sud. Hospital Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain.
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4
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Lam C, Gilliam KM, Rodden LN, Schadt KA, Lynch DR, Bidichandani S. FXN gene methylation determines carrier status in Friedreich ataxia. J Med Genet 2023; 60:797-800. [PMID: 36635061 PMCID: PMC10423546 DOI: 10.1136/jmg-2022-108742] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023]
Abstract
BACKGROUND Friedreich ataxia (FRDA) is typically caused by homozygosity for an expanded GAA triplet-repeat (GAA-TRE) in intron 1 of the FXN gene. Some patients are compound heterozygous for the GAA-TRE and another FXN pathogenic variant. Detection of the GAA-TRE in the heterozygous state, occasionally technically challenging, is essential for diagnosing compound heterozygotes and asymptomatic carriers. OBJECTIVE We explored if the FRDA differentially methylated region (FRDA-DMR) in intron 1, which is hypermethylated in cis with the GAA-TRE, effectively detects heterozygous GAA-TRE. METHODS FXN DNA methylation was assayed by targeted bisulfite deep sequencing using the Illumina platform. RESULTS FRDA-DMR methylation effectively identified a cohort of known heterozygous carriers of the GAA-TRE. In an individual with clinical features of FRDA, commercial testing showed a paternally inherited pathogenic FXN initiation codon variant but no GAA-TRE. Methylation in the FRDA-DMR effectively identified the proband, his mother and various maternal relatives as heterozygous carriers of the GAA-TRE, thus confirming the diagnosis of FRDA. CONCLUSION FXN DNA methylation reliably detects the GAA-TRE in the heterozygous state and offers a robust alternative strategy to diagnose FRDA due to compound heterozygosity and to identify asymptomatic heterozygous carriers of the GAA-TRE.
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Affiliation(s)
- Christina Lam
- Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Kaitlyn M Gilliam
- Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Layne N Rodden
- Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kimberly A Schadt
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - David R Lynch
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Sanjay Bidichandani
- Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Department of Biochemistry & Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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5
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Wang H, Wang LS, Schellenberg G, Lee WP. The role of structural variations in Alzheimer's disease and other neurodegenerative diseases. Front Aging Neurosci 2023; 14:1073905. [PMID: 36846102 PMCID: PMC9944073 DOI: 10.3389/fnagi.2022.1073905] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/31/2022] [Indexed: 02/10/2023] Open
Abstract
Dozens of single nucleotide polymorphisms (SNPs) related to Alzheimer's disease (AD) have been discovered by large scale genome-wide association studies (GWASs). However, only a small portion of the genetic component of AD can be explained by SNPs observed from GWAS. Structural variation (SV) can be a major contributor to the missing heritability of AD; while SV in AD remains largely unexplored as the accurate detection of SVs from the widely used array-based and short-read technology are still far from perfect. Here, we briefly summarized the strengths and weaknesses of available SV detection methods. We reviewed the current landscape of SV analysis in AD and SVs that have been found associated with AD. Particularly, the importance of currently less explored SVs, including insertions, inversions, short tandem repeats, and transposable elements in neurodegenerative diseases were highlighted.
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Affiliation(s)
- Hui Wang
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn Neurodegeneration Genomics Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Li-San Wang
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn Neurodegeneration Genomics Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Gerard Schellenberg
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn Neurodegeneration Genomics Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Wan-Ping Lee
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn Neurodegeneration Genomics Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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6
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Popoiu TA, Dudek J, Maack C, Bertero E. Cardiac Involvement in Mitochondrial Disorders. Curr Heart Fail Rep 2023; 20:76-87. [PMID: 36802007 PMCID: PMC9977856 DOI: 10.1007/s11897-023-00592-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/17/2022] [Indexed: 02/21/2023]
Abstract
PURPOSE OF REVIEW We review pathophysiology and clinical features of mitochondrial disorders manifesting with cardiomyopathy. RECENT FINDINGS Mechanistic studies have shed light into the underpinnings of mitochondrial disorders, providing novel insights into mitochondrial physiology and identifying new therapeutic targets. Mitochondrial disorders are a group of rare genetic diseases that are caused by mutations in mitochondrial DNA (mtDNA) or in nuclear genes that are essential to mitochondrial function. The clinical picture is extremely heterogeneous, the onset can occur at any age, and virtually, any organ or tissue can be involved. Since the heart relies primarily on mitochondrial oxidative metabolism to fuel contraction and relaxation, cardiac involvement is common in mitochondrial disorders and often represents a major determinant of their prognosis.
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Affiliation(s)
- Tudor-Alexandru Popoiu
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Wurzburg, Germany
- "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania
| | - Jan Dudek
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Wurzburg, Germany
| | - Christoph Maack
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Wurzburg, Germany
| | - Edoardo Bertero
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Wurzburg, Germany.
- Department of Internal Medicine and Specialties (Di.M.I.), University of Genoa, Genoa, Italy.
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7
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Hohenfeld C, Terstiege U, Dogan I, Giunti P, Parkinson MH, Mariotti C, Nanetti L, Fichera M, Durr A, Ewenczyk C, Boesch S, Nachbauer W, Klopstock T, Stendel C, Rodríguez de Rivera Garrido FJ, Schöls L, Hayer SN, Klockgether T, Giordano I, Didszun C, Rai M, Pandolfo M, Rauhut H, Schulz JB, Reetz K. Prediction of the disease course in Friedreich ataxia. Sci Rep 2022; 12:19173. [PMID: 36357508 PMCID: PMC9649725 DOI: 10.1038/s41598-022-23666-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
We explored whether disease severity of Friedreich ataxia can be predicted using data from clinical examinations. From the database of the European Friedreich Ataxia Consortium for Translational Studies (EFACTS) data from up to five examinations of 602 patients with genetically confirmed FRDA was included. Clinical instruments and important symptoms of FRDA were identified as targets for prediction, while variables such as genetics, age of disease onset and first symptom of the disease were used as predictors. We used modelling techniques including generalised linear models, support-vector-machines and decision trees. The scale for rating and assessment of ataxia (SARA) and the activities of daily living (ADL) could be predicted with predictive errors quantified by root-mean-squared-errors (RMSE) of 6.49 and 5.83, respectively. Also, we were able to achieve reasonable performance for loss of ambulation (ROC-AUC score of 0.83). However, predictions for the SCA functional assessment (SCAFI) and presence of cardiological symptoms were difficult. In conclusion, we demonstrate that some clinical features of FRDA can be predicted with reasonable error; being a first step towards future clinical applications of predictive modelling. In contrast, targets where predictions were difficult raise the question whether there are yet unknown variables driving the clinical phenotype of FRDA.
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Affiliation(s)
- Christian Hohenfeld
- grid.1957.a0000 0001 0728 696XDepartment of Neurology, RWTH Aachen University, 52074 Aachen, Germany ,grid.1957.a0000 0001 0728 696XJARA Brain Institute Molecular Neuroscience and Neuroimaging, Research Centre Jülich and RWTH Aachen University, 52056 Aachen, Germany
| | - Ulrich Terstiege
- grid.1957.a0000 0001 0728 696XChair for Mathematics of Information Processing, RWTH Aachen University, 52062 Aachen, Germany
| | - Imis Dogan
- grid.1957.a0000 0001 0728 696XDepartment of Neurology, RWTH Aachen University, 52074 Aachen, Germany ,grid.1957.a0000 0001 0728 696XJARA Brain Institute Molecular Neuroscience and Neuroimaging, Research Centre Jülich and RWTH Aachen University, 52056 Aachen, Germany
| | - Paola Giunti
- grid.83440.3b0000000121901201Department of Clinical and Movement Neurosciences, Ataxia Centre, UCL-Queen Square Institute of Neurology, London, WC1N 3BG UK
| | - Michael H. Parkinson
- grid.83440.3b0000000121901201Department of Clinical and Movement Neurosciences, Ataxia Centre, UCL-Queen Square Institute of Neurology, London, WC1N 3BG UK
| | - Caterina Mariotti
- grid.417894.70000 0001 0707 5492Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Lorenzo Nanetti
- grid.417894.70000 0001 0707 5492Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Mario Fichera
- grid.417894.70000 0001 0707 5492Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy ,grid.7563.70000 0001 2174 1754PhD Program in Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
| | - Alexandra Durr
- grid.411439.a0000 0001 2150 9058Sorbonne Université, Paris Brain Institute (ICM Institut du Cerveau), AP-HP, INSERM, CNRS, University Hospital Pitié-Salpêtrière, 75646 Paris, France
| | - Claire Ewenczyk
- grid.411439.a0000 0001 2150 9058Sorbonne Université, Paris Brain Institute (ICM Institut du Cerveau), AP-HP, INSERM, CNRS, University Hospital Pitié-Salpêtrière, 75646 Paris, France
| | - Sylvia Boesch
- grid.5361.10000 0000 8853 2677Department of Neurology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Wolfgang Nachbauer
- grid.5361.10000 0000 8853 2677Department of Neurology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Klopstock
- grid.5252.00000 0004 1936 973XDepartment of Neurology, Friedrich Baur Institute, University Hospital, LMU, 80336 Munich, Germany ,grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany ,grid.452617.3Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Claudia Stendel
- grid.5252.00000 0004 1936 973XDepartment of Neurology, Friedrich Baur Institute, University Hospital, LMU, 80336 Munich, Germany ,grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | | | - Ludger Schöls
- grid.10392.390000 0001 2190 1447Department of Neurology and Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany ,grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Stefanie N. Hayer
- grid.10392.390000 0001 2190 1447Department of Neurology and Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Thomas Klockgether
- grid.15090.3d0000 0000 8786 803XDepartment of Neurology, University Hospital of Bonn, 53127 Bonn, Germany ,grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Ilaria Giordano
- grid.15090.3d0000 0000 8786 803XDepartment of Neurology, University Hospital of Bonn, 53127 Bonn, Germany
| | - Claire Didszun
- grid.1957.a0000 0001 0728 696XDepartment of Neurology, RWTH Aachen University, 52074 Aachen, Germany
| | - Myriam Rai
- grid.4989.c0000 0001 2348 0746Laboratory of Experimental Neurology, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Massimo Pandolfo
- grid.4989.c0000 0001 2348 0746Laboratory of Experimental Neurology, Université Libre de Bruxelles, 1070 Brussels, Belgium ,grid.14709.3b0000 0004 1936 8649Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 0G4 Canada
| | - Holger Rauhut
- grid.1957.a0000 0001 0728 696XChair for Mathematics of Information Processing, RWTH Aachen University, 52062 Aachen, Germany
| | - Jörg B. Schulz
- grid.1957.a0000 0001 0728 696XDepartment of Neurology, RWTH Aachen University, 52074 Aachen, Germany ,grid.1957.a0000 0001 0728 696XJARA Brain Institute Molecular Neuroscience and Neuroimaging, Research Centre Jülich and RWTH Aachen University, 52056 Aachen, Germany
| | - Kathrin Reetz
- grid.1957.a0000 0001 0728 696XDepartment of Neurology, RWTH Aachen University, 52074 Aachen, Germany ,grid.1957.a0000 0001 0728 696XJARA Brain Institute Molecular Neuroscience and Neuroimaging, Research Centre Jülich and RWTH Aachen University, 52056 Aachen, Germany
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Jama M, Margraf RL, Yu P, Reading NS, Bayrak-Toydemir P. A Comprehensive Triple-Repeat Primed PCR and a Long-Range PCR Agarose-Based Assay for Improved Genotyping of Guanine-Adenine-Adenine Repeats in Friedreich Ataxia. J Mol Diagn 2022; 24:915-923. [PMID: 35595154 DOI: 10.1016/j.jmoldx.2022.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 11/18/2022] Open
Abstract
Friedreich ataxia is a rare autosomal recessive, neuromuscular degenerative disease caused by an expansion of a trinucleotide [guanine-adenine-adenine (GAA)] repeat in intron 1 of the FXN gene. It is common in the White population, characterized by progressive gait and limb ataxia, lack of tendon reflexes in the legs, loss of position sense, and hypertrophic cardiomyopathy. Detection and genotyping of the trinucleotide repeat length is important for the diagnosis and prognosis of the disease. A two-tier genotyping assay with an improved triple-repeat primed PCR (TR-PCR) for alleles <200 GAA repeats (±1 to 5 repeats) and an agarose gel-based, long-range PCR (LR-PCR) assay to genotype expanded alleles >200 GAA repeats (±50 repeats) is described. Of the 1236 DNA samples tested using TR-PCR, 31 were identified to have expanded alleles >200 repeats and were reflexed to the LR-PCR procedure for confirmation and quantification. The TR-PCR assay described herein is a diagnostic genotyping assay that reduces the need for further testing. The LR-PCR component is a confirmatory test for true homozygous and heterozygous samples with normal and expanded alleles, as indicated by the TR-PCR assay. The use of this two-tier method offers a comprehensive evaluation to detect and genotype the smallest and largest number of GAA repeats, improving the classification of FXN alleles as normal, mutable normal, borderline, and expanded alleles.
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Affiliation(s)
- Mohamed Jama
- Associated Regional and University Pathologists (ARUP) Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, Utah.
| | - Rebecca L Margraf
- Associated Regional and University Pathologists (ARUP) Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, Utah
| | - Ping Yu
- ARUP Laboratories, University of Utah, Salt Lake City, Utah
| | - N Scott Reading
- Associated Regional and University Pathologists (ARUP) Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, Utah; Department of Pathology, University of Utah, Salt Lake City, Utah
| | - Pinar Bayrak-Toydemir
- Associated Regional and University Pathologists (ARUP) Institute for Clinical and Experimental Pathology, University of Utah, Salt Lake City, Utah; Department of Pathology, University of Utah, Salt Lake City, Utah
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9
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Wang Q, Laboureur L, Weng L, Eskenazi NM, Hauser LA, Mesaros C, Lynch DR, Blair IA. Simultaneous Quantification of Mitochondrial Mature Frataxin and Extra-Mitochondrial Frataxin Isoform E in Friedreich’s Ataxia Blood. Front Neurosci 2022; 16:874768. [PMID: 35573317 PMCID: PMC9098139 DOI: 10.3389/fnins.2022.874768] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/22/2022] [Indexed: 11/25/2022] Open
Abstract
Friedreich’s ataxia (FRDA) is an autosomal recessive disease caused by an intronic guanine-adenine-adenine (GAA) triplet expansion in the frataxin (FXN) gene, which leads to reduced expression of full-length frataxin (1–210) also known as isoform 1. Full-length frataxin has a mitochondrial targeting sequence, which facilitates its translocation into mitochondria where it is processed through cleavage at G41-L42 and K80-S81 by mitochondrial processing (MPP) to release mitochondrial mature frataxin (81–210). Alternative splicing of FXN also leads to expression of N-terminally acetylated extra-mitochondrial frataxin (76–210) named isoform E because it was discovered in erythrocytes. Frataxin isoforms are undetectable in serum or plasma, and originally whole blood could not be used as a biomarker in brief therapeutic trials because it is present in erythrocytes, which have a half-life of 115-days and so frataxin levels would remain unaltered. Therefore, an assay was developed for analyzing frataxin in platelets, which have a half-life of only 10-days. However, our discovery that isoform E is only present in erythrocytes, whereas, mature frataxin is present primarily in short-lived peripheral blood mononuclear cells (PBMCs), granulocytes, and platelets, meant that both proteins could be quantified in whole blood samples. We now report a quantitative assay for frataxin proteoforms in whole blood from healthy controls and FRDA patients. The assay is based on stable isotope dilution coupled with immunoprecipitation (IP) and two-dimensional-nano-ultrahigh performance liquid chromatography/parallel reaction monitoring/high resolution mass spectrometry (2D-nano-UHPLC-PRM/HRMS). The lower limit of quantification was 0.5 ng/mL for each proteoform and the assays had 100% sensitivity and specificity for discriminating between healthy controls (n = 11) and FRDA cases (N = 100 in year-1, N = 22 in year-2,3). The mean levels of mature frataxin in whole blood from healthy controls and homozygous FRDA patients were significantly different (p < 0.0001) at 7.5 ± 1.5 ng/mL and 2.1 ± 1.2 ng/mL, respectively. The mean levels of isoform E in whole blood from healthy controls and homozygous FRDA patients were significantly different (p < 0.0001) at 26.8 ± 4.1 ng/mL and 4.7 ± 3.3 ng/mL, respectively. The mean levels of total frataxin in whole blood from healthy controls and homozygous FRDA patients were significantly different (p < 0.0001) at 34.2 ± 4.3 ng/mL and 6.8 ± 4.0 ng/mL, respectively. The assay will make it possible to rigorously monitor the natural history of the disease and explore the potential role of isoform E in etiology of the disease. It will also facilitate the assessment of therapeutic interventions (including gene therapy approaches) that attempt to increase frataxin protein expression as a treatment for this devastating disease.
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Affiliation(s)
- Qingqing Wang
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
| | - Laurent Laboureur
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
| | - Liwei Weng
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
| | - Nicolas M. Eskenazi
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
| | - Lauren A. Hauser
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
- Departments of Pediatrics and Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Departments of Pediatrics and Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Clementina Mesaros
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
| | - David R. Lynch
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
- Departments of Pediatrics and Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Departments of Pediatrics and Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ian A. Blair
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Penn/CHOP Center of Excellence in Friedreich’s Ataxia, Philadelphia, PA, United States
- *Correspondence: Ian A. Blair,
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10
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Lynch DR, Schadt K, Kichula E, McCormack S, Lin KY. Friedreich Ataxia: Multidisciplinary Clinical Care. J Multidiscip Healthc 2021; 14:1645-1658. [PMID: 34234452 PMCID: PMC8253929 DOI: 10.2147/jmdh.s292945] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/04/2021] [Indexed: 12/17/2022] Open
Abstract
Friedreich ataxia (FRDA) is a multisystem disorder affecting 1 in 50,000-100,000 person in the United States. Traditionally viewed as a neurodegenerative disease, FRDA patients also develop cardiomyopathy, scoliosis, diabetes and other manifestation. Although it usually presents in childhood, it continues throughout life, thus requiring expertise from both pediatric and adult subspecialist in order to provide optimal management. The phenotype of FRDA is unique, giving rise to specific loss of neuronal pathways, a unique form of cardiomyopathy with early hypertrophy and later fibrosis, and diabetes incorporating components of both type I and type II disease. Vision loss, hearing loss, urinary dysfunction and depression also occur in FRDA. Many agents are reaching Phase III trials; if successful, these will provide a variety of new treatments for FRDA that will require many specialists who are not familiar with FRDA to provide clinical therapy. This review provides a summary of the diverse manifestation of FRDA, existing symptomatic therapies, and approaches for integrative care for future therapy in FRDA.
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Affiliation(s)
- David R Lynch
- Division of Neurology, Departments of Pediatrics and Neurology, Children’s Hospital of Philadelphia and the Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Kim Schadt
- Division of Neurology, Departments of Pediatrics and Neurology, Children’s Hospital of Philadelphia and the Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Elizabeth Kichula
- Division of Neurology, Departments of Pediatrics and Neurology, Children’s Hospital of Philadelphia and the Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Shana McCormack
- Division of Endocrinology, Department of Pediatrics, Children’s Hospital of Philadelphia and the Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Kimberly Y Lin
- Division of Cardiology, Department of Pediatrics, Children’s Hospital of Philadelphia and the Perelman School of Medicine, Philadelphia, PA, 19104, USA
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11
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Replication-independent instability of Friedreich's ataxia GAA repeats during chronological aging. Proc Natl Acad Sci U S A 2021; 118:2013080118. [PMID: 33495349 PMCID: PMC7865128 DOI: 10.1073/pnas.2013080118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The inheritance of long (GAA)n repeats in the frataxin gene causes the debilitating neurodegenerative disease Friedreich’s ataxia. Subsequent expansions of these repeats throughout a patient’s lifetime in the affected tissues, like the nervous system, may contribute to disease onset. We developed an experimental model to characterize the mechanisms of repeat instability in nondividing cells to better understand how mutations can occur as cells age chronologically. We show that repeats can expand in nondividing cells. Notably, however, large deletions are the major type of repeat-mediated genome instability in nondividing cells, implicating the loss of important genetic material with aging in the progression of Friedreich’s ataxia. Nearly 50 hereditary diseases result from the inheritance of abnormally long repetitive DNA microsatellites. While it was originally believed that the size of inherited repeats is the key factor in disease development, it has become clear that somatic instability of these repeats throughout an individual’s lifetime strongly contributes to disease onset and progression. Importantly, somatic instability is commonly observed in terminally differentiated, postmitotic cells, such as neurons. To unravel the mechanisms of repeat instability in nondividing cells, we created an experimental system to analyze the mutability of Friedreich’s ataxia (GAA)n repeats during chronological aging of quiescent Saccharomyces cerevisiae. Unexpectedly, we found that the predominant repeat-mediated mutation in nondividing cells is large-scale deletions encompassing parts, or the entirety, of the repeat and adjacent regions. These deletions are caused by breakage at the repeat mediated by mismatch repair (MMR) complexes MutSβ and MutLα and DNA endonuclease Rad1, followed by end-resection by Exo1 and repair of the resulting double-strand breaks (DSBs) via nonhomologous end joining. We also observed repeat-mediated gene conversions as a result of DSB repair via ectopic homologous recombination during chronological aging. Repeat expansions accrue during chronological aging as well—particularly in the absence of MMR-induced DSBs. These expansions depend on the processivity of DNA polymerase δ while being counteracted by Exo1 and MutSβ, implicating nick repair. Altogether, these findings show that the mechanisms and types of (GAA)n repeat instability differ dramatically between dividing and nondividing cells, suggesting that distinct repeat-mediated mutations in terminally differentiated somatic cells might influence Friedreich’s ataxia pathogenesis.
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12
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Smith FM, Kosman DJ. Molecular Defects in Friedreich's Ataxia: Convergence of Oxidative Stress and Cytoskeletal Abnormalities. Front Mol Biosci 2020; 7:569293. [PMID: 33263002 PMCID: PMC7686857 DOI: 10.3389/fmolb.2020.569293] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/10/2020] [Indexed: 01/18/2023] Open
Abstract
Friedreich’s ataxia (FRDA) is a multi-faceted disease characterized by progressive sensory–motor loss, neurodegeneration, brain iron accumulation, and eventual death by hypertrophic cardiomyopathy. FRDA follows loss of frataxin (FXN), a mitochondrial chaperone protein required for incorporation of iron into iron–sulfur cluster and heme precursors. After the discovery of the molecular basis of FRDA in 1996, over two decades of research have been dedicated to understanding the temporal manifestations of disease both at the whole body and molecular level. Early research indicated strong cellular iron dysregulation in both human and yeast models followed by onset of oxidative stress. Since then, the pathophysiology due to dysregulation of intracellular iron chaperoning has become central in FRDA relative to antioxidant defense and run-down in energy metabolism. At the same time, limited consideration has been given to changes in cytoskeletal organization, which was one of the first molecular defects noted. These alterations include both post-translational oxidative glutathionylation of actin monomers and differential DNA processing of a cytoskeletal regulator PIP5K1β. Currently unknown in respect to FRDA but well understood in the context of FXN-deficient cell physiology is the resulting impact on the cytoskeleton; this disassembly of actin filaments has a particularly profound effect on cell–cell junctions characteristic of barrier cells. With respect to a neurodegenerative disorder such as FRDA, this cytoskeletal and tight junction breakdown in the brain microvascular endothelial cells of the blood–brain barrier is likely a component of disease etiology. This review serves to outline a brief history of this research and hones in on pathway dysregulation downstream of iron-related pathology in FRDA related to actin dynamics. The review presented here was not written with the intent of being exhaustive, but to instead urge the reader to consider the essentiality of the cytoskeleton and appreciate the limited knowledge on FRDA-related cytoskeletal dysfunction as a result of oxidative stress. The review examines previous hypotheses of neurodegeneration with brain iron accumulation (NBIA) in FRDA with a specific biochemical focus.
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Affiliation(s)
- Frances M Smith
- Department of Biochemistry, State University of New York at Buffalo, Buffalo, NY, United States
| | - Daniel J Kosman
- Department of Biochemistry, State University of New York at Buffalo, Buffalo, NY, United States
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13
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Gottesfeld JM. Molecular Mechanisms and Therapeutics for the GAA·TTC Expansion Disease Friedreich Ataxia. Neurotherapeutics 2019; 16:1032-1049. [PMID: 31317428 PMCID: PMC6985418 DOI: 10.1007/s13311-019-00764-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Friedreich ataxia (FRDA), the most common inherited ataxia, is caused by transcriptional silencing of the nuclear FXN gene, encoding the essential mitochondrial protein frataxin. Currently, there is no approved therapy for this fatal disorder. Gene silencing in FRDA is due to hyperexpansion of the triplet repeat sequence GAA·TTC in the first intron of the FXN gene, which results in chromatin histone modifications consistent with heterochromatin formation. Frataxin is involved in mitochondrial iron homeostasis and the assembly and transfer of iron-sulfur clusters to various mitochondrial enzymes and components of the electron transport chain. Frataxin insufficiency leads to progressive spinocerebellar neurodegeneration, causing symptoms of gait and limb ataxia, slurred speech, muscle weakness, sensory loss, and cardiomyopathy in many patients, resulting in death in early adulthood. Numerous approaches are being taken to find a treatment for FRDA, including excision or correction of the repeats by genome engineering methods, gene activation with small molecules or artificial transcription factors, delivery of frataxin to affected cells by protein replacement therapy, gene therapy, or small molecules to increase frataxin protein levels, and therapies aimed at countering the cellular consequences of reduced frataxin. This review will summarize the mechanisms involved in repeat-mediated gene silencing and recent efforts aimed at development of therapeutics.
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Affiliation(s)
- Joel M Gottesfeld
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, 92037, USA.
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14
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Sayah S, Rotgé JY, Francisque H, Gargiulo M, Czernecki V, Justo D, Lahlou-Laforet K, Hahn V, Pandolfo M, Pelissolo A, Fossati P, Durr A. Personality and Neuropsychological Profiles in Friedreich Ataxia. THE CEREBELLUM 2019; 17:204-212. [PMID: 29086357 DOI: 10.1007/s12311-017-0890-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Friedreich ataxia, an autosomal recessive mitochondrial disease, is the most frequent inherited ataxia. Many studies have attempted to identify cognitive and affective changes associated with the disease, but conflicting results have been obtained, depending on the tests used and because many of the samples studied were very small. We investigated personality and neuropsychological characteristics in a cohort of 47 patients with genetically confirmed disease. The neuropsychological battery assessed multiple cognition domains: processing speed, attention, working memory, executive functions, verbal memory, vocabulary, visual reasoning, emotional recognition, and social cognition. Personality was assessed with the Temperament and Character Inventory, and depressive symptoms were assessed with the Beck Depression Inventory. We found deficits of sustained attention, processing speed, semantic capacities, and verbal fluency only partly attributable to motor deficit or depressed mood. Visual reasoning, memory, and learning were preserved. Emotional processes and social cognition were unimpaired. We also detected a change in automatic processes, such as reading. Personality traits were characterized by high persistence and low self-transcendence. The mild cognitive impairment observed may be a developmental rather than degenerative problem, due to early cerebellum dysfunction, with the impairment of cognitive and emotional processing. Disease manifestations at crucial times for personality development may also have an important impact on personality traits.
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Affiliation(s)
- Sabrina Sayah
- AP-HP, Genetic Department, Pitié-Salpêtrière University Hospital, Paris, France.,ICM, Institut du Cerveau et de la Moelle Epinière, INSERM U1127, CNRS UMR7225, Sorbonne Universités - UPMC Université Paris VI UMR_S1127, Paris, France
| | - Jean-Yves Rotgé
- ICM, Institut du Cerveau et de la Moelle Epinière, INSERM U1127, CNRS UMR7225, Sorbonne Universités - UPMC Université Paris VI UMR_S1127, Paris, France.,AP-HP, Service de Psychiatrie, Pitié-Salpêtrière University Hospital, Paris, France
| | - Hélène Francisque
- APHP, Hôpitaux Universitaires Saint Louis Lariboisière Fernand-Widal, Paris, France
| | - Marcela Gargiulo
- AP-HP, Genetic Department, Pitié-Salpêtrière University Hospital, Paris, France.,Institut de Myologie, Pitié-Salpêtrière University Hospital, Paris, France.,Laboratoire de Psychologie Clinique et Psychopathologie, EA 4056, Université Paris Descartes, Sorbonne Paris Cité, Institut de Psychologie, Paris, France
| | - Virginie Czernecki
- AP-HP, Département des Maladies du Système Nerveux, Pitié-Salpêtrière University Hospital, Paris, France
| | - Damian Justo
- Unité de neurologie de la Mémoire et du Langage, Centre Hospitalier Sainte-Anne, Paris, France
| | - Khadija Lahlou-Laforet
- Unité de Psychologie et Psychiatrie de Liaison et d'Urgences, Hôpital Européen Georges Pompidou, Service de Psychiatrie Adulte et du Sujet Agé, Hôpitaux Universitaires Paris-Ouest, Paris, France
| | - Valérie Hahn
- Unité de neurologie de la Mémoire et du Langage, Centre Hospitalier Sainte-Anne, Paris, France
| | - Massimo Pandolfo
- Service de Neurologie, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Pelissolo
- AP-HP, Service de Psychiatrie, Hôpitaux Universitaires Henri-Mondor, Créteil, France
| | - Philippe Fossati
- ICM, Institut du Cerveau et de la Moelle Epinière, INSERM U1127, CNRS UMR7225, Sorbonne Universités - UPMC Université Paris VI UMR_S1127, Paris, France.,AP-HP, Service de Psychiatrie, Pitié-Salpêtrière University Hospital, Paris, France
| | - Alexandra Durr
- AP-HP, Genetic Department, Pitié-Salpêtrière University Hospital, Paris, France. .,ICM, Institut du Cerveau et de la Moelle Epinière, INSERM U1127, CNRS UMR7225, Sorbonne Universités - UPMC Université Paris VI UMR_S1127, Paris, France. .,ICM, Institut du Cerveau et de la Moelle épinière, Groupe Hospitalier Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France.
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15
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Abstract
Friedreich's ataxia (FRDA) is a degenerative disease that affects both the central and the peripheral nervous systems and non-neural tissues including, mainly, heart, and endocrine pancreas. It is an autosomal recessive disease caused by a GAA triplet-repeat localized within an Alu sequence element in intron 1 of frataxin (FXN) gene, which encodes a mitochondrial protein FXN. This protein is essential for mitochondrial function by the involvement of iron-sulfur cluster biogenesis. The effects of its deficiency also include disruption of cellular, particularly mitochondrial, iron homeostasis, i.e., relatively more iron accumulated in mitochondria and less iron presented in cytosol. Though iron toxicity is commonly thought to be mediated via Fenton reaction, oxidative stress seems not to be the main problem to result in detrimental effects on cell survival, particularly neuron survival. Therefore, the basic research on FXN function is urgently demanded to understand the disease. This chapter focuses on the outcome of FXN expression, regulation, and function in cellular or animal models of FRDA and on iron pathophysiology in the affected tissues. Finally, therapeutic strategies based on the control of iron toxicity and iron cellular redistribution are considered. The combination of multiple therapeutic targets including iron, oxidative stress, mitochondrial function, and FXN regulation is also proposed.
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Affiliation(s)
- Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, People's Republic of China.
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16
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Barcia G, Rachid M, Magen M, Assouline Z, Koenig M, Funalot B, Barnerias C, Rötig A, Munnich A, Bonnefont JP, Steffann J. Pitfalls in molecular diagnosis of Friedreich ataxia. Eur J Med Genet 2018; 61:455-458. [PMID: 29530802 DOI: 10.1016/j.ejmg.2018.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/08/2018] [Accepted: 03/08/2018] [Indexed: 11/27/2022]
Abstract
Freidreich ataxia (FRDA) is the most common hereditary ataxia, nearly 98% of patients harbouring homozygous GAA expansions in intron 1 of the FXN gene (NM_000144.4). The remaining patients are compound heterozygous for an expansion and a point mutation or an exonic deletion. Molecular screening for FXN expansion is therefore focused on (GAA)n expansion analysis, commonly performed by triplet repeat primed PCR (PT-PCR). We report on an initial pitfall in the molecular characterization of a 15 year-old girl with Freidreich ataxia (FRDA) who carried a rare deletion in intron 1 of the FXN gene. Due to this deletion TP-PCR failed to amplify the GAA expansion. This exceptional configuration induced misinterpretation of the molecular defect in this patient, who was first reported as having no FXN expansion. NGS analysis of a panel of 212 genes involved in nuclear mitochondrial disorders further revealed an intragenic deletion encompassing exons 4-5 of the FXN gene. Modified TP-PCR analysis confirmed the presence of a classical (GAA)n expansion located in trans. This case points out the possible pitfalls in molecular diagnosis of FRDA in affected patients and their relatives: detection of the FXN expansion may be impaired by several non-pathological or pathological variants around the FXN (GAA)n repeat. We propose a new molecular strategy to accurately detect expansion by TP-PCR in FRDA patients.
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Affiliation(s)
- Giulia Barcia
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France; Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Myriam Rachid
- Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Maryse Magen
- Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Zahra Assouline
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France; Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares, Institut Universitaire de Recherche Clinique, EA7402 Université de Montpellier, Montpellier Cedex, France
| | - Benoit Funalot
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France; Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Christine Barnerias
- Service de neurologie pédiatrique et maladies métaboliques, Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Agnès Rötig
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France
| | - Arnold Munnich
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France; Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Jean-Paul Bonnefont
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France; Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France
| | - Julie Steffann
- Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, INSERM UMR1163, Laboratoire des Maladies Mitochondriales, Paris, France; Service de Génétique, Groupe hospitalier Necker Enfants Malades, Assistance Publique -Hôpitaux de Paris, Paris, France.
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17
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Autonomic function testing in Friedreich's ataxia. J Neurol 2018; 265:2015-2022. [PMID: 29951702 PMCID: PMC6132658 DOI: 10.1007/s00415-018-8946-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/13/2018] [Accepted: 06/16/2018] [Indexed: 12/17/2022]
Abstract
Background Friedreich ataxia (FRDA) is an inherited movement disorder which manifests with progressive gait instability, sensory loss and cardiomyopathy. Peripheral neuropathy is an established feature of FRDA. At neuropathological examination, a depletion of large, myelinated axons is evident, but also unmyelinated fibers are affected which may result in a variety of sensory and autonomic signs and symptoms. Impaired temperature perception, vasomotor disturbances of lower extremities and a high prevalence of urinary symptoms have been documented in FRDA, but data from autonomic function testing in genetically confirmed cases are lacking. Methods Genetically confirmed FRDAs were recruited in an outpatient setting. In a screening visit, general and neurological examination, laboratory testing, ECG and echocardiography were performed. Autonomic functions were evaluated by means of systematic questionnaires (SCOPA-Aut, OHQ), skin sympathetic reflex and cardiovascular autonomic function testing (CAFT). For the latter, a comparison with matched healthy controls was performed. Results 20 patients were recruited and 13 underwent CAFT. Symptoms referred to multiple autonomic domains, particularly bladder function, thermoregulation and sweating were reported. SCOPA-Aut scores were significantly predicted by disease severity. At CAFT, FRDAs did not differ from controls except for increased heart rate at rest and during orthostatic challenge. Two patients had non-neurogenic orthostatic hypotension (14%). Skin sympathetic responses were pathologic in 3 out of 10 patients (of whom 2 aged > 50). Conclusions FRDA patients may experience several autonomic symptoms and overall their burden correlates with disease severity. Nonetheless, clinical testing shows no major involvement of sudomotor and cardiovascular autonomic function.
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Abstract
More than 40 diseases, most of which primarily affect the nervous system, are caused by expansions of simple sequence repeats dispersed throughout the human genome. Expanded trinucleotide repeat diseases were discovered first and remain the most frequent. More recently tetra-, penta-, hexa-, and even dodeca-nucleotide repeat expansions have been identified as the cause of human disease, including some of the most common genetic disorders seen by neurologists. Repeat expansion diseases include both causes of myotonic dystrophy (DM1 and DM2), the most common genetic cause of amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72), Huntington disease, and eight other polyglutamine disorders, including the most common forms of dominantly inherited ataxia, the most common recessive ataxia (Friedreich ataxia), and the most common heritable mental retardation (fragile X syndrome). Here I review distinctive features of this group of diseases that stem from the unusual, dynamic nature of the underlying mutations. These features include marked clinical heterogeneity and the phenomenon of clinical anticipation. I then discuss the diverse molecular mechanisms driving disease pathogenesis, which vary depending on the repeat sequence, size, and location within the disease gene, and whether the repeat is translated into protein. I conclude with a brief clinical and genetic description of individual repeat expansion diseases that are most relevant to neurologists.
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Affiliation(s)
- Henry Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.
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19
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Bürk K. Friedreich Ataxia: current status and future prospects. CEREBELLUM & ATAXIAS 2017; 4:4. [PMID: 28405347 PMCID: PMC5383992 DOI: 10.1186/s40673-017-0062-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/24/2017] [Indexed: 01/23/2023]
Abstract
Friedreich ataxia (FA) represents the most frequent type of inherited ataxia. Most patients carry homozygous GAA expansions in the first intron of the frataxin gene on chromosome 9. Due to epigenetic alterations, frataxin expression is significantly reduced. Frataxin is a mitochondrial protein. Its deficiency leads to mitochondrial iron overload, defective energy supply and generation of reactive oxygen species. This review gives an overview over clinical and genetic aspects of FA and discusses current concepts of frataxin biogenesis and function as well as new therapeutic strategies.
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Affiliation(s)
- Katrin Bürk
- University of Marburg, and Paracelsus-Elena Klinik, Klinikstr. 16, 34128 Kassel, Germany
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20
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Hoffman-Zacharska D, Mazurczak T, Zajkowski T, Tataj R, Górka-Skoczylas P, Połatyńska K, Kępczyński Ł, Stasiołek M, Bal J. Friedreich ataxia is not only a GAA repeats expansion disorder: implications for molecular testing and counselling. J Appl Genet 2016; 57:349-55. [PMID: 26906906 DOI: 10.1007/s13353-015-0331-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/25/2015] [Accepted: 12/07/2015] [Indexed: 10/22/2022]
Abstract
Friedreich ataxia (FRDA) is the most common hereditary ataxia. It is an autosomal recessive disorder caused by mutations of the FXN gene, mainly the biallelic expansion of the (GAA)n repeats in its first intron. Heterozygous expansion/point mutations or deletions are rare; no patients with two point mutations or a point mutation/deletion have been described, suggesting that loss of the FXN gene product, frataxin, is lethal. This is why routine FRDA molecular diagnostics is focused on (GAA)n expansion analysis. Additional tests are considered only in cases of heterozygous expansion carriers and an atypical clinical picture. Analyses of the parent's carrier status, together with diagnostic tests, are performed in rare cases, and, because of that, we may underestimate the frequency of deletions. Even though FXN deletions are characterised as 'exquisitely rare,' we were able to identify one case (2.4 %) of a (GAA)n expansion/exonic deletion in a group of 41 probands. This was a patient with very early onset of disease with rapid progression of gait instability and hypertrophic cardiomyopathy. We compared the patient's clinical data to expansion/deletion carriers available in the literature and suggest that, in clinical practice, the FXN deletion test should be taken into account in patients with early-onset, rapid progressive ataxia and severe scoliosis.
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Affiliation(s)
- Dorota Hoffman-Zacharska
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01 211, Warsaw, Poland.
- Institute of Genetics and Biotechnology, Warsaw University, Warsaw, Poland.
| | - Tomasz Mazurczak
- Clinic of Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Tomasz Zajkowski
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01 211, Warsaw, Poland
- Institute of Genetics and Biotechnology, Warsaw University, Warsaw, Poland
| | - Renata Tataj
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01 211, Warsaw, Poland
| | - Paulina Górka-Skoczylas
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01 211, Warsaw, Poland
- Clinic of Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Katarzyna Połatyńska
- Department of Neurology, Polish Mother's Memorial Hospital-Research Institute, Łódź, Poland
| | - Łukasz Kępczyński
- Molecular Biology Unit, Department of Internal Diseases and Nephrodiabetology, Medical University of Łódz, Łódz, Poland
| | - Mariusz Stasiołek
- Department of Neurology, Polish Mother's Memorial Hospital-Research Institute, Łódź, Poland
| | - Jerzy Bal
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01 211, Warsaw, Poland
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21
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Galea CA, Huq A, Lockhart PJ, Tai G, Corben LA, Yiu EM, Gurrin LC, Lynch DR, Gelbard S, Durr A, Pousset F, Parkinson M, Labrum R, Giunti P, Perlman SL, Delatycki MB, Evans-Galea MV. Compound heterozygous FXN mutations and clinical outcome in friedreich ataxia. Ann Neurol 2016; 79:485-95. [PMID: 26704351 DOI: 10.1002/ana.24595] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Friedreich ataxia (FRDA) is an inherited neurodegenerative disease characterized by ataxia and cardiomyopathy. Homozygous GAA trinucleotide repeat expansions in the first intron of FXN occur in 96% of affected individuals and reduce frataxin expression. Remaining individuals are compound heterozygous for a GAA expansion and a FXN point/insertion/deletion mutation. We examined disease-causing mutations and the impact on frataxin structure/function and clinical outcome in FRDA. METHODS We compared clinical information from 111 compound heterozygotes and 131 individuals with homozygous expansions. Frataxin mutations were examined using structural modeling, stability analyses and systematic literature review, and categorized into four groups: (1) homozygous expansions, and three compound heterozygote groups; (2) null (no frataxin produced); (3) moderate/strong impact; and (4) minimal impact. Mean age of onset and the presence of cardiomyopathy and diabetes mellitus were compared using regression analyses. RESULTS Mutations in the hydrophobic core of frataxin affected stability whereas surface residue mutations affected interactions with iron sulfur cluster assembly and heme biosynthetic proteins. The null group of compound heterozygotes had significantly earlier age of onset and increased diabetes mellitus, compared to the homozygous expansion group. There were no significant differences in mean age of onset between homozygotes and the minimal and moderate/strong impact groups. INTERPRETATION In compound heterozygotes, expression of partially functional mutant frataxin delays age of onset and reduces diabetes mellitus, compared to those with no frataxin expression from the non-expanded allele. This integrated analysis of categorized frataxin mutations and their correlation with clinical outcome provide a definitive resource for investigating disease pathogenesis in FRDA.
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Affiliation(s)
- Charles A Galea
- Medicinal Chemistry and Drug Delivery, Disposition and Dynamics (D4), Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Aamira Huq
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Geneieve Tai
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Louise A Corben
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Eppie M Yiu
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Neurology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Lyle C Gurrin
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - David R Lynch
- Departments of Neurology and Pediatrics, University of Pennsylvania School of Medicine and The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Sarah Gelbard
- Departments of Neurology and Pediatrics, University of Pennsylvania School of Medicine and The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Alexandra Durr
- APHP, Department of Genetics and Cytogenetics, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Pitié-Salpêtrière University Hospital, Paris, France
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 06 UMR S_1127, ICM, F-75013, France
| | - Francoise Pousset
- APHP, Cardiology Department, AP-HP Pitie-Salpétrière Hospital, Paris, France
| | - Michael Parkinson
- Department of Molecular Neuroscience, University College London Institute of Neurology, London, United Kingdom
| | - Robyn Labrum
- Department of Neurogenetics, University College London Hospital, Institute of Neurology, London, United Kingdom
| | - Paola Giunti
- Department of Molecular Neuroscience, University College London Institute of Neurology, London, United Kingdom
- Department of Neurogenetics, University College London Hospital, Institute of Neurology, London, United Kingdom
| | - Susan L Perlman
- Ataxia Center and Huntington Disease Center of Excellence, Department of Neurology, David Geffen School of Medicine at the University of California at Los Angeles, CA
| | - Martin B Delatycki
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
- Clinical Genetics, Austin Health, Heidelberg, Victoria, Australia
| | - Marguerite V Evans-Galea
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
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22
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Lecocq C, Charles P, Azulay JP, Meissner W, Rai M, N'Guyen K, Péréon Y, Fabre N, Robin E, Courtois S, Guyant-Maréchal L, Zagnoli F, Rudolf G, Renaud M, Sévin-Allouet M, Lesne F, Alaerts N, Goizet C, Calvas P, Eusebio A, Guissart C, Derkinderen P, Tison F, Brice A, Koenig M, Pandolfo M, Tranchant C, Dürr A, Anheim M. Delayed-onset Friedreich's ataxia revisited. Mov Disord 2015; 31:62-9. [PMID: 26388117 DOI: 10.1002/mds.26382] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 06/30/2015] [Accepted: 07/06/2015] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Friedreich's ataxia usually occurs before the age of 25. Rare variants have been described, such as late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia, occurring after 25 and 40 years, respectively. We describe the clinical, functional, and molecular findings from a large series of late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia and compare them with typical-onset Friedreich's ataxia. METHODS Phenotypic and genotypic comparison of 44 late-onset Friedreich's ataxia, 30 very late-onset Friedreich's ataxia, and 180 typical Friedreich's ataxia was undertaken. RESULTS Delayed-onset Friedreich's ataxia (late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia) had less frequently dysarthria, abolished tendon reflexes, extensor plantar reflexes, weakness, amyotrophy, ganglionopathy, cerebellar atrophy, scoliosis, and cardiomyopathy than typical-onset Friedreich's ataxia, along with less severe functional disability and shorter GAA expansion on the smaller allele (P < 0.001). Delayed-onset Friedreich's ataxia had lower scale for the assessment and rating of ataxia and spinocerebellar degeneration functional scores and longer disease duration before wheelchair confinement (P < 0.001). Both GAA expansions were negatively correlated to age at disease onset (P < 0.001), but the smaller GAA expansion accounted for 62.9% of age at onset variation and the larger GAA expansion for 15.6%. In this comparative study of late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia, no differences between these phenotypes were demonstrated. CONCLUSION Typical- and delayed-onset Friedreich's ataxia are different and Friedreich's ataxia is heterogeneous. Late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia appear to belong to the same clinical and molecular continuum and should be considered together as "delayed-onset Friedreich's ataxia." As the most frequently inherited ataxia, Friedreich's ataxia should be considered facing compatible pictures, including atypical phenotypes (spastic ataxia, retained reflexes, lack of dysarthria, and lack of extraneurological signs), delayed disease onset (even after 60 years of age), and/or slow disease progression.
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Affiliation(s)
- Claire Lecocq
- Département de Neurologie, Hôpital de Hautepierre, CHU de Strasbourg, Strasbourg, France
| | - Perrine Charles
- Département de Génétique et Cytogénétique, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France
| | - Jean-Philippe Azulay
- Département de Neurologie et Pathologie du mouvement, Hôpital de la Timone, Marseille, France
| | - Wassilios Meissner
- Université De Bordeaux, Institut des Maladies Neurodégénératives, CNRS UMR 5293, Bordeaux, France; and Département de Neurologie, Hôpital Pellegrin, CHU de Bordeaux, Bordeaux, France
| | - Myriam Rai
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Karine N'Guyen
- Département de Neurologie et Pathologie du mouvement, Hôpital de la Timone, Marseille, France
| | - Yann Péréon
- Laboratoire d'Explorations Fonctionnelles, Centre de Référence Maladies Neuromusculaires Nantes-Angers, Hôtel-Dieu, CHU Nantes, Nantes, France
| | - Nelly Fabre
- Département de Neurologie, Hôpital Purpan, CHU de Toulouse, Toulouse, France
| | - Elsa Robin
- Département de Neurologie et Pathologie du mouvement, Hôpital de la Timone, Marseille, France
| | - Sylvie Courtois
- Département de Neurologie, Hôpital Emile-Muller, Mulhouse, France
| | | | | | - Gabrielle Rudolf
- Département de Neurologie, Hôpital de Hautepierre, CHU de Strasbourg, Strasbourg, France
| | - Mathilde Renaud
- Département de Neurologie, Hôpital de Hautepierre, CHU de Strasbourg, Strasbourg, France
| | | | - Fabien Lesne
- UPMC Université Paris 06, UMR_S975, Centre de Recherche Institut du Cerveau et de la Moelle, CNRS 7225, Hôpital de la Pitié-Salpêtrière, Paris, France; and INSERM, UMR_S975, Paris, France
| | - Nick Alaerts
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Cyril Goizet
- CHU Bordeaux, Service de Génétique Médicale, Université Bordeaux, Laboratoire Maladies Rares: Génétique et Métabolisme (MRGM), EA4576, Bordeaux, France
| | - Patrick Calvas
- Département de Neurologie, Hôpital Purpan, CHU de Toulouse, Toulouse, France; and Service de Génétique Médicale, Hôpital Purpan, CHU de Toulouse, Toulouse, France
| | - Alexandre Eusebio
- Département de Neurologie et Pathologie du mouvement, Hôpital de la Timone, Marseille, France
| | - Claire Guissart
- Laboratoire de Génétique Moléculaire, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU Montpellier, Montpellier, France
| | - Pascal Derkinderen
- Département de Neurologie, Hôpital GR Laënnec, CHU de Nantes, Nantes, France
| | - Francois Tison
- Université De Bordeaux, Institut des Maladies Neurodégénératives, CNRS UMR 5293, Bordeaux, France; and Département de Neurologie, Hôpital Pellegrin, CHU de Bordeaux, Bordeaux, France
| | - Alexis Brice
- Département de Génétique et Cytogénétique, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France; UPMC Université Paris 06, UMR_S975, Centre de Recherche Institut du Cerveau et de la Moelle, CNRS 7225, Hôpital de la Pitié-Salpêtrière, Paris, France; and INSERM, UMR_S975, Paris, France
| | - Michel Koenig
- Laboratoire de Génétique Moléculaire, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU Montpellier, France; and Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch, France
| | - Massimo Pandolfo
- Laboratoire de Neurologie Expérimentale, Université Libre de Bruxelles (ULB), Brussels, Belgium; and Département de Neurologie, Hôpital Erasme, Brussels, Belgium
| | - Christine Tranchant
- Département de Neurologie, Hôpital de Hautepierre, CHU de Strasbourg, Strasbourg, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch, France; and Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
| | - Alexandra Dürr
- Département de Génétique et Cytogénétique, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France; UPMC Université Paris 06, UMR_S975, Centre de Recherche Institut du Cerveau et de la Moelle, CNRS 7225, Hôpital de la Pitié-Salpêtrière, Paris, France; and INSERM, UMR_S975, Paris, France
| | - Mathieu Anheim
- Département de Neurologie, Hôpital de Hautepierre, CHU de Strasbourg, France Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch, France; and Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
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23
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Wedding IM, Kroken M, Henriksen SP, Selmer KK, Fiskerstrand T, Knappskog PM, Berge T, Tallaksen CME. Friedreich ataxia in Norway - an epidemiological, molecular and clinical study. Orphanet J Rare Dis 2015; 10:108. [PMID: 26338206 PMCID: PMC4559212 DOI: 10.1186/s13023-015-0328-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/25/2015] [Indexed: 01/06/2023] Open
Abstract
Background Friedreich ataxia is an autosomal recessive hereditary spinocerebellar disorder, characterized by progressive limb and gait ataxia due to proprioceptive loss, often complicated by cardiomyopathy, diabetes and skeletal deformities. Friedreich ataxia is the most common hereditary ataxia, with a reported prevalence of 1:20 000 – 1:50 000 in Central Europe. Previous reports from south Norway have found a prevalence varying from 1:100 000 – 1:1 350 000; no studies are previously done in the rest of the country. Methods In this cross-sectional study, Friedreich ataxia patients were identified through colleagues in neurological, pediatric and genetic departments, hospital archives searches, patients’ associations, and National Centre for Rare Disorders. All included patients, carriers and controls were investigated clinically and molecularly with genotype characterization including size determination of GAA repeat expansions and frataxin measurements. 1376 healthy blood donors were tested for GAA repeat expansion for carrier frequency analysis. Results Twenty-nine Friedreich ataxia patients were identified in Norway, of which 23 were ethnic Norwegian, corresponding to a prevalence of 1:176 000 and 1:191 000, respectively. The highest prevalence was seen in the north. Carrier frequency of 1:196 (95 % CI = [1:752–1:112]) was found. Homozygous GAA repeat expansions in the FXN gene were found in 27/29, while two patients were compound heterozygous with c.467 T < C, L157P and the deletion (g.120032_122808del) including exon 5a. Two additional patients were heterozygous for GAA repeat expansions only. Significant differences in the level of frataxin were found between the included patients (N = 27), carriers (N = 37) and controls (N = 27). Conclusions In this first thorough study of a complete national cohort of Friedreich ataxia patients, and first nation-wide study of Friedreich ataxia in Norway, the prevalence of Friedreich ataxia in Norway is lower than in Central Europe, but higher than in the last Norwegian report, and as expected from migration studies. A south–north prevalence gradient is present. Based on Hardy Weinberg’s equilibrium, the carrier frequency of 1:196 is consistent with the observed prevalence. All genotypes, and typical and atypical phenotypes were present in the Norwegian population. The patients were phenotypically similar to European cohorts. Frataxin was useful in the diagnostic work-up of heterozygous symptomatic cases. Electronic supplementary material The online version of this article (doi:10.1186/s13023-015-0328-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Iselin Marie Wedding
- Department of Neurology, Oslo University Hospital, Ullevaal, 0407, Oslo, Norway. .,University of Oslo, Faculty of Medicine, Oslo, Norway.
| | - Mette Kroken
- Department of Medical Genetics, Oslo University Hospital, Ullevaal, 0407, Oslo, Norway
| | | | - Kaja Kristine Selmer
- Department of Medical Genetics, Oslo University Hospital, Ullevaal, 0407, Oslo, Norway.,University of Oslo, Faculty of Medicine, Oslo, Norway
| | - Torunn Fiskerstrand
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Per Morten Knappskog
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Tone Berge
- Department of Neurology, Oslo University Hospital, Ullevaal, 0407, Oslo, Norway
| | - Chantal M E Tallaksen
- Department of Neurology, Oslo University Hospital, Ullevaal, 0407, Oslo, Norway.,University of Oslo, Faculty of Medicine, Oslo, Norway
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24
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Lazaropoulos M, Dong Y, Clark E, Greeley NR, Seyer LA, Brigatti KW, Christie C, Perlman SL, Wilmot GR, Gomez CM, Mathews KD, Yoon G, Zesiewicz T, Hoyle C, Subramony SH, Brocht AF, Farmer JM, Wilson RB, Deutsch EC, Lynch DR. Frataxin levels in peripheral tissue in Friedreich ataxia. Ann Clin Transl Neurol 2015; 2:831-42. [PMID: 26339677 PMCID: PMC4554444 DOI: 10.1002/acn3.225] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 12/30/2022] Open
Abstract
Objective Friedreich ataxia (FRDA) is an autosomal recessive ataxia resulting from mutations in the frataxin gene (FXN). Such mutations, usually expanded guanine–adenine–adenine (GAA) repeats, give rise to decreased levels of frataxin protein in both affected and unaffected tissues. The goal was to understand the relationship of frataxin levels in peripheral tissues to disease status. Methods Frataxin levels were measured in buccal cells and blood, and analyzed in relation to disease features. Site-directed mutant frataxin was also transfected into human embryonic kidney cells to model results from specific point mutations. Results There was no evidence for change in frataxin levels over time with repeated measures analysis, although linear regression analysis of cross-sectional data predicted a small increase over decades. GAA repeat length predicted frataxin levels in both tissues, and frataxin levels themselves predicted neurological ratings (accounting for age). Compound heterozygous patients for a GAA expansion and a point mutation in FXN generally had lower levels of frataxin than those homozygous for the presence of two GAA repeat expansions, though levels varied dramatically between tissues in some compound heterozygotes for point mutations. The G130V mutation led to decreased levels of frataxin in vitro as well as in vivo, while the R165C mutation produced normal immunoreactive levels of frataxin both in vitro and in vivo. Start codon mutations led to low levels of frataxin in buccal cells but preserved immunoreactive frataxin levels in blood. Interpretation The present data show that peripheral frataxin levels reflect disease features in FRDA, but emphasize the need for interpretation of such levels in the context of specific mutations.
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Affiliation(s)
- Michael Lazaropoulos
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Yina Dong
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Elisia Clark
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Nathaniel R Greeley
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Lauren A Seyer
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Karlla W Brigatti
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Carlton Christie
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Susan L Perlman
- Department of Neurology, University of California Los Angeles Los Angeles, California
| | | | | | | | - Grace Yoon
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto Toronto, Ontario, Canada
| | | | - Chad Hoyle
- Department of Neurology, The Ohio State University Columbus, Ohio
| | - Sub H Subramony
- Department of Neurology, University of Florida Gainesville, Florida
| | - Alicia F Brocht
- Department of Neurology, University of Rochester Rochester, New York
| | - Jennifer M Farmer
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Robert B Wilson
- Department of Pathology and Lab Medicine, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - Eric C Deutsch
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
| | - David R Lynch
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania, 19104
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25
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Abrahão A, Pedroso JL, Braga-Neto P, Bor-Seng-Shu E, de Carvalho Aguiar P, Barsottini OGP. Milestones in Friedreich ataxia: more than a century and still learning. Neurogenetics 2015; 16:151-60. [PMID: 25662948 DOI: 10.1007/s10048-015-0439-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/20/2015] [Indexed: 10/24/2022]
Abstract
Friedreich ataxia (FRDA) is the most common autosomal recessive ataxia worldwide. This review highlights the main clinical features, pathophysiological mechanisms, and therapeutic approaches for FRDA patients. The disease is characterized by a combination of neurological involvement (ataxia and neuropathy), cardiomyopathy, skeletal abnormalities, and glucose metabolism disturbances. FRDA is caused by expanded guanine-adenine-adenine (GAA) triplet repeats in the first intron of the frataxin gene (FXN), resulting in reduction of messenger RNA and protein levels of frataxin in different tissues. The molecular and metabolic disturbances, including iron accumulation, lead to pathological changes characterized by spinal cord and dorsal root ganglia atrophy, dentate nucleus atrophy without global cerebellar volume reduction, and hypertrophic cardiomyopathy. DNA analysis is the hallmark for the diagnosis of FRDA. There is no specific treatment to stop the disease progression in FRDA patients. However, a number of drugs are under investigation. Therapeutic approaches intend to improve mitochondrial functioning and to increase FXN expression.
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Affiliation(s)
- Agessandro Abrahão
- Division of General Neurology and Ataxia Unit, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, Rua Pedro de Toledo 650 Vila Clementino, São Paulo, 04039-002, SP, Brazil,
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26
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Zeng J, Wang J, Zeng S, He M, Zeng X, Zhou Y, Liu Z, Jiang H, Tang B. Friedreich's Ataxia (FRDA) is an extremely rare cause of autosomal recessive ataxia in Chinese Han population. J Neurol Sci 2015; 351:124-126. [PMID: 25765228 DOI: 10.1016/j.jns.2015.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/01/2015] [Indexed: 10/23/2022]
Abstract
Friedreich's Ataxia (FRDA) is a very common cause of hereditary autosomal recessive ataxia among western Europeans. We aim to define the frequency of FRDA in Chinese Han population due to the lack of reports of FRDA in China. The GAA trinucleotide repeats in the FXN gene were analyzed by triplet repeat-primed PCR (TP-PCR) in 122 unrelated hereditary ataxia (HA) and 114 unrelated hereditary spastic paraplegia (HSP) patients. The GAA copy numbers in the FXN gene of all the subjects ranged from 5 to 16. There were no FRDA patients that could be diagnosed base on the results of TP-PCR. It suggests that FRDA is a very rare cause of inheritance ataxia and FRDA genetic analysis should not be used as a routine genetic diagnosis test in China.
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Affiliation(s)
- Junsheng Zeng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Junling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Changsha, Hunan, PR China; State Key Laboratory of Medical Genetics, Changsha, Hunan, PR China
| | - Sheng Zeng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Miao He
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Xianfeng Zeng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Yao Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Zhen Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Changsha, Hunan, PR China; State Key Laboratory of Medical Genetics, Changsha, Hunan, PR China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Changsha, Hunan, PR China; State Key Laboratory of Medical Genetics, Changsha, Hunan, PR China.
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Maio N, Rouault TA. Iron-sulfur cluster biogenesis in mammalian cells: New insights into the molecular mechanisms of cluster delivery. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1493-512. [PMID: 25245479 DOI: 10.1016/j.bbamcr.2014.09.009] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/07/2014] [Indexed: 01/19/2023]
Abstract
Iron-sulfur (Fe-S) clusters are ancient, ubiquitous cofactors composed of iron and inorganic sulfur. The combination of the chemical reactivity of iron and sulfur, together with many variations of cluster composition, oxidation states and protein environments, enables Fe-S clusters to participate in numerous biological processes. Fe-S clusters are essential to redox catalysis in nitrogen fixation, mitochondrial respiration and photosynthesis, to regulatory sensing in key metabolic pathways (i.e. cellular iron homeostasis and oxidative stress response), and to the replication and maintenance of the nuclear genome. Fe-S cluster biogenesis is a multistep process that involves a complex sequence of catalyzed protein-protein interactions and coupled conformational changes between the components of several dedicated multimeric complexes. Intensive studies of the assembly process have clarified key points in the biogenesis of Fe-S proteins. However several critical questions still remain, such as: what is the role of frataxin? Why do some defects of Fe-S cluster biogenesis cause mitochondrial iron overload? How are specific Fe-S recipient proteins recognized in the process of Fe-S transfer? This review focuses on the basic steps of Fe-S cluster biogenesis, drawing attention to recent advances achieved on the identification of molecular features that guide selection of specific subsets of nascent Fe-S recipients by the cochaperone HSC20. Additionally, it outlines the distinctive phenotypes of human diseases due to mutations in the components of the basic pathway. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Nunziata Maio
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 9000 Rockville Pike, 20892 Bethesda, MD, USA
| | - Tracey A Rouault
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 9000 Rockville Pike, 20892 Bethesda, MD, USA.
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Recessive spinocerebellar ataxia with paroxysmal cough attacks: a report of five cases. THE CEREBELLUM 2014; 13:215-21. [PMID: 24097205 DOI: 10.1007/s12311-013-0526-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hereditary ataxias are a heterogeneous group of neurological diseases characterized by progressive cerebellar syndrome and numerous other features, which result in great diversity of ataxia subtypes. Despite the characterization of a number of both autosomal dominant and autosomal recessive ataxias, it is thought that a large group of these conditions remains to be identified. In this study, we report the characterization of five patients (three Mexicans and two Italians) who exhibit a peculiar form of recessive ataxia associated with coughing. The main clinical and neurophysiological features of these patients include cerebellar ataxia, paroxysmal cough, restless legs syndrome (RLS), choreic movements, atrophy of distal muscles, and oculomotor disorders. Brain magnetic resonance imaging (MRI) revealed cerebellar atrophy, while video polysomnography (VPSG) studies showed a severe pattern of breathing-related sleep disorder, including sleep apnea, snoring, and significant oxygen saturation in the absence of risk factors. All patients share clinical features in the peripheral nervous system, including reduction of amplitude and prolonged latency of sensory potentials in median and sural nerves. Altogether, clinical criteria as well as molecular genetic testing that was negative for different autosomal dominant and autosomal recessive ataxias suggest the presence of a new form of recessive ataxia. This ataxia, in which cerebellar signs are preceded by paroxysmal cough, affects not only the cerebellum and its fiber connections, but also the sensory peripheral nervous system and extracerebellar central pathways.
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Greeley NR, Regner S, Willi S, Lynch DR. Cross-sectional analysis of glucose metabolism in Friedreich ataxia. J Neurol Sci 2014; 342:29-35. [PMID: 24819921 DOI: 10.1016/j.jns.2014.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 04/08/2014] [Accepted: 04/12/2014] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To evaluate the relationship between disease features in Friedreich ataxia and aberrant glucose metabolism. METHODS Fasting glucose, fasting insulin and random HbA1C were obtained in 158 patients with Friedreich ataxia. Regression analysis evaluated glucose, insulin, and homeostatic model assessment (HOMA) of insulin resistance (IR) and beta-cell function (ß) in relation to age, BMI, sex, and genetic severity. Categorical glucose values were analyzed in relation to other FRDA-associated disease characteristics. RESULTS In the FRDA cohort, age and GAA repeat length predicted fasting glucose and HbA1c levels (accounting for sex and BMI), while insulin and HOMA-IR were not predicted by these parameters. Within the cohort, average BMI was consistently lower than the national average by age and was marginally associated with insulin levels and HOMA-IR. Within juvenile subjects, insulin and HOMA-IR were predicted by age. Controlling for age and genetic severity, diabetes-related measures were not independent predictors of any quantitative measure of disease severity in FRDA. Glucose handling properties were also predicted by the presence of a point mutation, with 40% of individuals heterozygous for point mutations having diabetes, compared to 4.3% of subjects who carried two expanded GAA repeats. INTERPRETATION In FRDA, aberrant glucose metabolism is linked to increasing age, longer GAA repeat length on the shorter allele, frataxin point mutations, and increasing BMI. The effect of age to some degree may be mediated through changes in BMI, with increasing age associated with increases in BMI, and with HOMA-IR and insulin increases in children.
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Affiliation(s)
- Nathaniel R Greeley
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States.
| | - Sean Regner
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States.
| | - Steve Willi
- Division of Endocrinology and Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, United States.
| | - David R Lynch
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Neurology, University of Pennsylvania Medical School, Philadelphia, PA, United States; Department of Pediatrics, University of Pennsylvania Medical School, Philadelphia, PA, United States.
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Puccio H, Anheim M, Tranchant C. Pathophysiogical and therapeutic progress in Friedreich ataxia. Rev Neurol (Paris) 2014; 170:355-65. [PMID: 24792433 DOI: 10.1016/j.neurol.2014.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 01/10/2023]
Abstract
Friedreich ataxia (FRDA) is the most common hereditary autosomal recessive ataxia, but is also a multisystemic condition with frequent presence of cardiomyopathy or diabetes. It has been linked to expansion of a GAA-triplet repeat in the first intron of the FXN gene, leading to a reduced level of frataxin, a mitochondrial protein which, by controlling both iron entry and/or sulfide production, is essential to properly assemble and protect the Fe-S cluster during the initial stage of biogenesis. Several data emphasize the role of oxidative damage in FRDA, but better understanding of pathophysiological consequences of FXN mutations has led to develop animal models. Conditional knockout models recapitulate important features of the human disease but lack the genetic context, GAA repeat expansion-based knock-in and transgenic models carry a GAA repeat expansion but they only show a very mild phenotype. Cells derived from FRDA patients constitute the most relevant frataxin-deficient cell model as they carry the complete frataxin locus together with GAA repeat expansions and regulatory sequences. Induced pluripotent stem cell (iPSC)-derived neurons present a maturation delay and lower mitochondrial membrane potential, while cardiomyocytes exhibit progressive mitochondrial degeneration, with frequent dark mitochondria and proliferation/accumulation of normal mitochondria. Efforts in developing therapeutic strategies can be divided into three categories: iron chelators, antioxidants and/or stimulants of mitochondrial biogenesis, and frataxin level modifiers. A promising therapeutic strategy that is currently the subject of intense research is to directly target the heterochromatin state of the GAA repeat expansion with histone deacytelase inhibitors (HDACi) to restore frataxin levels.
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Affiliation(s)
- H Puccio
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Collège de France, chaire de génétique humaine, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France
| | - M Anheim
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Service de neurologie, unité des pathologies du mouvement, hôpital de Hautepierre, hôpital universitaire, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - C Tranchant
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Service de neurologie, unité des pathologies du mouvement, hôpital de Hautepierre, hôpital universitaire, 1, place de l'Hôpital, 67000 Strasbourg, France.
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Sandi C, Sandi M, Jassal H, Ezzatizadeh V, Anjomani-Virmouni S, Al-Mahdawi S, Pook MA. Generation and characterisation of Friedreich ataxia YG8R mouse fibroblast and neural stem cell models. PLoS One 2014; 9:e89488. [PMID: 24586819 PMCID: PMC3931792 DOI: 10.1371/journal.pone.0089488] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/20/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disease caused by GAA repeat expansion in the first intron of the FXN gene, which encodes frataxin, an essential mitochondrial protein. To further characterise the molecular abnormalities associated with FRDA pathogenesis and to hasten drug screening, the development and use of animal and cellular models is considered essential. Studies of lower organisms have already contributed to understanding FRDA disease pathology, but mammalian cells are more related to FRDA patient cells in physiological terms. METHODOLOGY/PRINCIPAL FINDINGS We have generated fibroblast cells and neural stem cells (NSCs) from control Y47R mice (9 GAA repeats) and GAA repeat expansion YG8R mice (190+120 GAA repeats). We then differentiated the NSCs in to neurons, oligodendrocytes and astrocytes as confirmed by immunocytochemical analysis of cell specific markers. The three YG8R mouse cell types (fibroblasts, NSCs and differentiated NSCs) exhibit GAA repeat stability, together with reduced expression of frataxin and reduced aconitase activity compared to control Y47R cells. Furthermore, YG8R cells also show increased sensitivity to oxidative stress and downregulation of Pgc-1α and antioxidant gene expression levels, especially Sod2. We also analysed various DNA mismatch repair (MMR) gene expression levels and found that YG8R cells displayed significant reduction in expression of several MMR genes, which may contribute to the GAA repeat stability. CONCLUSIONS/SIGNIFICANCE We describe the first fibroblast and NSC models from YG8R FRDA mice and we confirm that the NSCs can be differentiated into neurons and glia. These novel FRDA mouse cell models, which exhibit a FRDA-like cellular and molecular phenotype, will be valuable resources to further study FRDA molecular pathogenesis. They will also provide very useful tools for preclinical testing of frataxin-increasing compounds for FRDA drug therapy, for gene therapy, and as a source of cells for cell therapy testing in FRDA mice.
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Affiliation(s)
- Chiranjeevi Sandi
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Madhavi Sandi
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Harvinder Jassal
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Vahid Ezzatizadeh
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Sara Anjomani-Virmouni
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Sahar Al-Mahdawi
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Mark A. Pook
- Ataxia Research Group, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
- * E-mail:
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Oglesbee D, Kroll C, Gakh O, Deutsch EC, Lynch DR, Gavrilova R, Tortorelli S, Raymond K, Gavrilov D, Rinaldo P, Matern D, Isaya G. High-throughput immunoassay for the biochemical diagnosis of Friedreich ataxia in dried blood spots and whole blood. Clin Chem 2013; 59:1461-9. [PMID: 23838345 PMCID: PMC3914541 DOI: 10.1373/clinchem.2013.207472] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Friedreich ataxia (FRDA) is caused by reduced frataxin (FXN) concentrations. A clinical diagnosis is typically confirmed by DNA-based assays for GAA-repeat expansions or mutations in the FXN (frataxin) gene; however, these assays are not applicable to therapeutic monitoring and population screening. To facilitate the diagnosis and monitoring of FRDA patients, we developed an immunoassay for measuring FXN. METHODS Antibody pairs were used to capture FXN and an internal control protein, ceruloplasmin (CP), in 15 μL of whole blood (WB) or one 3-mm punch of a dried blood spot (DBS). Samples were assayed on a Luminex LX200 analyzer and validated according to standard criteria. RESULTS The mean recovery of FXN from WB and DBS samples was 99%. Intraassay and interassay imprecision (CV) values were 4.9%-13% and 9.8%-16%, respectively. The FXN limit of detection was 0.07 ng/mL, and the reportable range of concentrations was 2-200 ng/mL. Reference adult and pediatric FXN concentrations ranged from 15 to 82 ng/mL (median, 33 ng/mL) for DBS and WB. The FXN concentration range was 12-22 ng/mL (median, 15 ng/mL) for FRDA carriers and 1-26 ng/mL (median 5 ng/mL) for FRDA patients. Measurement of the FXN/CP ratio increased the ability to distinguish between patients, carriers, and the reference population. CONCLUSIONS This assay is applicable to the diagnosis and therapeutic monitoring of FRDA. This assay can measure FXN and the control protein CP in both WB and DBS specimens with minimal sample requirements, creating the potential for high-throughput population screening of FRDA.
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Affiliation(s)
- Devin Oglesbee
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
- Department of Medical Genetics, Mayo Clinic College of Medicine, Rochester, MN
| | - Charles Kroll
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
| | - Oleksandr Gakh
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN
| | - Eric C. Deutsch
- Department of Neurology, University of Pennsylvania, Philadelphia, PA
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA
- Department of Pharmacology, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - David R. Lynch
- Department of Neurology, University of Pennsylvania, Philadelphia, PA
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA
- Department of Pharmacology, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - Ralitza Gavrilova
- Department of Medical Genetics, Mayo Clinic College of Medicine, Rochester, MN
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Silvia Tortorelli
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
| | - Kimiyo Raymond
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
| | - Dimitar Gavrilov
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Piero Rinaldo
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Dietrich Matern
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN
- Department of Medical Genetics, Mayo Clinic College of Medicine, Rochester, MN
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Grazia Isaya
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
- Mayo Clinic Children’s Center, Rochester, MN
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Parkinson MH, Boesch S, Nachbauer W, Mariotti C, Giunti P. Clinical features of Friedreich's ataxia: classical and atypical phenotypes. J Neurochem 2013; 126 Suppl 1:103-17. [PMID: 23859346 DOI: 10.1111/jnc.12317] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/15/2013] [Accepted: 05/15/2013] [Indexed: 11/27/2022]
Abstract
One hundred and fifty years since Nikolaus Friedreich's first description of the degenerative ataxic syndrome which bears his name, his description remains at the core of the classical clinical phenotype of gait and limb ataxia, poor balance and coordination, leg weakness, sensory loss, areflexia, impaired walking, dysarthria, dysphagia, eye movement abnormalities, scoliosis, foot deformities, cardiomyopathy and diabetes. Onset is typically around puberty with slow progression and shortened life-span often related to cardiac complications. Inheritance is autosomal recessive with the vast majority of cases showing an unstable intronic GAA expansion in both alleles of the frataxin gene on chromosome 9q13. A small number of cases are caused by a compound heterozygous expansion with a point mutation or deletion. Understanding of the underlying molecular biology has enabled identification of atypical phenotypes with late onset, or atypical features such as retained reflexes. Late-onset cases tend to have slower progression and are associated with smaller GAA expansions. Early-onset cases tend to have more rapid progression and a higher frequency of non-neurological features such as diabetes, cardiomyopathy, scoliosis and pes cavus. Compound heterozygotes, including those with large deletions, often have atypical features. In this paper, we review the classical and atypical clinical phenotypes of Friedreich's ataxia.
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Affiliation(s)
- Michael H Parkinson
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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Saccà F, Marsili A, Puorro G, Antenora A, Pane C, Tessa A, Scoppettuolo P, Nesti C, Brescia Morra V, De Michele G, Santorelli FM, Filla A. Clinical use of frataxin measurement in a patient with a novel deletion in the FXN gene. J Neurol 2013; 260:1116-21. [PMID: 23196337 DOI: 10.1007/s00415-012-6770-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/11/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Abstract
Friedreich ataxia (FRDA) is caused by a GAA expansion in the first intron of the FXN gene, which encodes frataxin. Four percent of patients harbor a point mutation on one allele and a GAA expansion on the other. We studied an Italian patient presenting with symptoms suggestive of FRDA, and carrying a single expanded 850 GAA allele. As a second diagnostic step, frataxin was measured in peripheral blood mononuclear cells, and proved to be in the pathological range (2.95 pg/μg total protein, 12.7 % of control levels). Subsequent sequencing revealed a novel deletion in exon 5a (c.572delC) which predicted a frameshift at codon 191 and a premature truncation of the protein at codon 194 (p.T191IfsX194). FXN/mRNA expression was reduced to 69.2 % of control levels. Clinical phenotype was atypical with absent dysarthria, and rapid disease progression. L-Buthionine-sulphoximine treatment of the proband's lymphoblasts showed a severe phenotype as compared to classic FRDA.
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Affiliation(s)
- Francesco Saccà
- Department of Neurological Sciences, University Federico II, Via Pansini 5, 80131 Naples, NA, Italy.
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Epigenetics in Friedreich's Ataxia: Challenges and Opportunities for Therapy. GENETICS RESEARCH INTERNATIONAL 2013; 2013:852080. [PMID: 23533785 PMCID: PMC3590757 DOI: 10.1155/2013/852080] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/10/2013] [Indexed: 11/17/2022]
Abstract
Friedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by homozygous expansion of a GAA·TTC trinucleotide repeat within the first intron of the FXN gene, leading to reduced FXN transcription and decreased levels of frataxin protein. Recent advances in FRDA research have revealed the presence of several epigenetic modifications that are either directly or indirectly involved in this FXN gene silencing. Although epigenetic marks may be inherited from one generation to the next, modifications of DNA and histones can be reversed, indicating that they are suitable targets for epigenetic-based therapy. Unlike other trinucleotide repeat disorders, such as Huntington disease, the large expansions of GAA·TTC repeats in FRDA do not produce a change in the frataxin amino acid sequence, but they produce reduced levels of normal frataxin. Therefore, transcriptional reactivation of the FXN gene provides a good therapeutic option. The present paper will initially focus on the epigenetic changes seen in FRDA patients and their role in the silencing of FXN gene and will be concluded by considering the potential epigenetic therapies.
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