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Xu IRL, Danzi MC, Ruiz A, Raposo J, De Jesus YA, Reilly MM, Cortese A, Shy ME, Scherer SS, Hermann D, Fridman V, Baets J, Saporta M, Seyedsadjadi R, Stojkovic T, Claeys KG, Patel P, Feely S, Rebelo A, Dohrn MF, Züchner S. A study concept of expeditious clinical enrollment for genetic modifier studies in Charcot-Marie-Tooth neuropathy 1A. J Peripher Nerv Syst 2024; 29:202-212. [PMID: 38581130 PMCID: PMC11209807 DOI: 10.1111/jns.12621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/01/2024] [Accepted: 03/07/2024] [Indexed: 04/08/2024]
Abstract
BACKGROUND Caused by duplications of the gene encoding peripheral myelin protein 22 (PMP22), Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common hereditary neuropathy. Despite this shared genetic origin, there is considerable variability in clinical severity. It is hypothesized that genetic modifiers contribute to this heterogeneity, the identification of which may reveal novel therapeutic targets. In this study, we present a comprehensive analysis of clinical examination results from 1564 CMT1A patients sourced from a prospective natural history study conducted by the RDCRN-INC (Inherited Neuropathy Consortium). Our primary objective is to delineate extreme phenotype profiles (mild and severe) within this patient cohort, thereby enhancing our ability to detect genetic modifiers with large effects. METHODS We have conducted large-scale statistical analyses of the RDCRN-INC database to characterize CMT1A severity across multiple metrics. RESULTS We defined patients below the 10th (mild) and above the 90th (severe) percentiles of age-normalized disease severity based on the CMT Examination Score V2 and foot dorsiflexion strength (MRC scale). Based on extreme phenotype categories, we defined a statistically justified recruitment strategy, which we propose to use in future modifier studies. INTERPRETATION Leveraging whole genome sequencing with base pair resolution, a future genetic modifier evaluation will include single nucleotide association, gene burden tests, and structural variant analysis. The present work not only provides insight into the severity and course of CMT1A, but also elucidates the statistical foundation and practical considerations for a cost-efficient and straightforward patient enrollment strategy that we intend to conduct on additional patients recruited globally.
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Affiliation(s)
- Isaac R. L. Xu
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Matt C. Danzi
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Ariel Ruiz
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Jacquelyn Raposo
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Yeisha Arcia De Jesus
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Mary M Reilly
- Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square
| | - Andrea Cortese
- Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square
| | - Michael E Shy
- Department of Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Steven S. Scherer
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - David Hermann
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 673, Rochester, New York, 14642, USA
| | - Vera Fridman
- Department of Neurology, University of Colorado Anschutz Medical Campus, 12631 E 17th Avenue, Mailstop B185, Room 5113C, Aurora, CO, 80045, USA
| | - Jonathan Baets
- Department of Neurology, Neuromuscular Reference Centre, Antwerp University Hospital, Antwerp, Belgium
- Faculty of Medicine and Health Sciences, Translational Neurosciences, University of Antwerp, Antwerp, Belgium
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Mario Saporta
- Department of Neurology, University of Miami Miller School of Medicine, United States
| | - Reza Seyedsadjadi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tanya Stojkovic
- AP-HP, Centre de référence des maladies neuromusculaires Nord/Est/Ile de France, Hôpital Pitié-Salpêtrière, 47-83, boulevard de l’Hôpital, 75013 Paris, France
| | - Kristl G. Claeys
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Laboratory for Muscle Diseases and Neuropathies, KU Leuven, Leuven, Belgium
| | - Pooja Patel
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Shawna Feely
- Department of Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Adriana Rebelo
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | | | - Maike F. Dohrn
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
- Department of Neurology, Medical Faculty of the RWTH Aachen University, Aachen, Germany
| | - Stephan Züchner
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
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Murray GC, Hines TJ, Tadenev ALD, Xu I, Züchner S, Burgess RW. Testing SIPA1L2 as a modifier of CMT1A using mouse models. J Neuropathol Exp Neurol 2024; 83:318-330. [PMID: 38472136 PMCID: PMC11029467 DOI: 10.1093/jnen/nlae020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024] Open
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is a demyelinating peripheral neuropathy caused by the duplication of peripheral myelin protein 22 (PMP22), leading to muscle weakness and loss of sensation in the hands and feet. A recent case-only genome-wide association study of CMT1A patients conducted by the Inherited Neuropathy Consortium identified a strong association between strength of foot dorsiflexion and variants in signal induced proliferation associated 1 like 2 (SIPA1L2), indicating that it may be a genetic modifier of disease. To validate SIPA1L2 as a candidate modifier and to assess its potential as a therapeutic target, we engineered mice with deletion of exon 1 (including the start codon) of the Sipa1l2 gene and crossed them to the C3-PMP22 mouse model of CMT1A. Neuromuscular phenotyping showed that Sipa1l2 deletion in C3-PMP22 mice preserved muscular endurance assayed by inverted wire hang duration and changed femoral nerve axon morphometrics such as myelin thickness. Gene expression changes suggest involvement of Sipa1l2 in cholesterol biosynthesis, a pathway that is also implicated in C3-PMP22 mice. Although Sipa1l2 deletion did impact CMT1A-associated phenotypes, thereby validating a genetic interaction, the overall effect on neuropathy was mild.
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Affiliation(s)
- George C Murray
- The Jackson Laboratory, Bar Harbor, Maine, USA
- The Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, Maine, USA
| | | | | | - Isaac Xu
- Department of Human Genetics and John P Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Stephan Züchner
- Department of Human Genetics and John P Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, Maine, USA
- The Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, Maine, USA
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3
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Murray GC, Hines TJ, Tadenev ALD, Xu I, Züchner S, Burgess RW. Testing SIPA1L2 as a modifier of CMT1A using mouse models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569428. [PMID: 38076977 PMCID: PMC10705403 DOI: 10.1101/2023.11.30.569428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Charcot-Marie-Tooth 1A is a demyelinating peripheral neuropathy caused by the duplication of peripheral myelin protein 22 (PMP22), which produces muscle weakness and loss of sensation in the hands and feet. A recent case-only genome wide association study by the Inherited Neuropathy Consortium identified a strong association between variants in signal induced proliferation associated 1 like 2 (SIPA1L2) and strength of foot dorsiflexion. To validate SIPA1L2 as a candidate modifier, and to assess its potential as a therapeutic target, we engineered mice with a deletion in SIPA1L2 and crossed them to the C3-PMP22 mouse model of CMT1A. We performed neuromuscular phenotyping and identified an interaction between Sipa1l2 deletion and muscular endurance decrements assayed by wire-hang duration in C3-PMP22 mice, as well as several interactions in femoral nerve axon morphometrics such as myelin thickness. Gene expression changes suggested an involvement of Sipa1l2 in cholesterol biosynthesis, which was also implicated in C3-PMP22 mice. Though several interactions between Sipa1l2 deletion and CMT1A-associated phenotypes were identified, validating a genetic interaction, the overall effect on neuropathy was small.
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Affiliation(s)
- George C Murray
- The Jackson Laboratory, Bar Harbor, ME 04609
- The Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, ME 04469
| | | | | | - Isaac Xu
- Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Stephan Züchner
- Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609
- The Graduate School of Biomedical Science and Engineering, The University of Maine, Orono, ME 04469
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4
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Rehbein T, Wu TT, Treidler S, Pareyson D, Lewis R, Yum SW, McCray BA, Ramchandren S, Burns J, Li J, Finkel RS, Scherer SS, Zuchner S, Shy ME, Reilly MM, Herrmann DN. Neuropathy due to bi-allelic SH3TC2 variants: genotype-phenotype correlation and natural history. Brain 2023; 146:3826-3835. [PMID: 36947133 PMCID: PMC10473553 DOI: 10.1093/brain/awad095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/23/2023] [Accepted: 03/05/2023] [Indexed: 03/23/2023] Open
Abstract
Recessive SH3TC2 variants cause Charcot-Marie-Tooth disease type 4C (CMT4C). CMT4C is typically a sensorimotor demyelinating polyneuropathy, marked by early onset spinal deformities, but its clinical characteristics and severity are quite variable. Clear relationships between pathogenic variants and the spectrum of disease manifestations are to date lacking. Gene replacement therapy has been shown to ameliorate the phenotype in a mouse model of CMT4C, emphasizing the need for natural history studies to inform clinical trial readiness. Data, including both genetic information and clinical characteristics, were compiled from the longitudinal, prospective dataset of the Inherited Neuropathy Consortium, a member of the Rare Diseases Clinical Research Network (INC-RDCRN). The Charcot Marie Tooth Neuropathy Score (CMTNS), Examination Score (CMTES) and the Rasch-weighted CMTES (CMTES-R) were used to describe symptoms, neurological examinations and neurophysiological characteristics. Standardized response means were calculated at yearly intervals and a mixed model for repeated measures was used to estimate the change in CMTES and CMTES-R over time. Fifty-six individuals (59% female), median age 27 years (range 2-67 years) with homozygous or compound heterozygous variants in SH3TC2 were identified, including 34 unique variants, 14 of which have not previously been published. Twenty-eight participants had longitudinal data available. While there was no significant difference in the CMTES in those with protein truncating versus non-protein truncating variants, there were significant differences in the mean ulnar nerve compound muscle action potential amplitude, the mean radial sensory nerve action potential amplitude, and in the prevalence of scoliosis, suggesting the possibility of a milder phenotype in individuals with one or two non-protein-truncating variants. Overall, the mean value of the CMTES was 13, reflecting moderate clinical severity. There was a high rate of scoliosis (81%), scoliosis surgery (36%), and walking difficulty (94%) among study participants. The CMTES and CMTES-R appeared moderately responsive to change over extended follow-up, demonstrating a standardized response mean of 0.81 standard deviation units or 0.71 standard deviation units, respectively, over 3 years. Our analysis represents the largest cross-sectional and only longitudinal study to date, of the clinical phenotype of both adults and children with CMT4C. With the promise of upcoming genetic treatments, these data will further define the natural history of the disease and inform study design in preparation for clinical trials.
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Affiliation(s)
- Tyler Rehbein
- Department of Neurology, University of Rochester, Rochester, NY 14642, USA
| | - Tong Tong Wu
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY 14642, USA
| | - Simona Treidler
- Department of Neurology, Stony Brook University, Stony Brook, NY 11790, USA
| | - Davide Pareyson
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Richard Lewis
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Sabrina W Yum
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Brett A McCray
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Sindhu Ramchandren
- Clinical Development Department - Neuroscience, The Janssen Pharmaceutical Companies of Johnson & Johnson, Titusville, NJ 08560, USA
| | - Joshua Burns
- Faculty of Medicine and Health; Paediatric Gait Analysis Service of New South Wales, University of Sydney School of Health Sciences, Sydney Children’s Hospitals Network, Sydney 2031, Australia
| | - Jun Li
- Department of Neurology, Houston Methodist Hospital, Houston, TX 77030, USA
| | - Richard S Finkel
- Center for Experimental Neurotherapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33101, USA
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Mary M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - David N Herrmann
- Department of Neurology, University of Rochester, Rochester, NY 14642, USA
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5
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Pisciotta C, Shy ME. Hereditary neuropathy. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:609-617. [PMID: 37562889 DOI: 10.1016/b978-0-323-98818-6.00009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The hereditary neuropathies, collectively referred as Charcot-Marie-Tooth disease (CMT) and related disorders, are heterogeneous genetic peripheral nerve disorders that collectively comprise the commonest inherited neurological disease with an estimated prevalence of 1:2500 individuals. The field of hereditary neuropathies has made significant progress in recent years with respect to both gene discovery and treatment as a result of next-generation sequencing (NGS) approach. These investigations which have identified over 100 causative genes and new mutations have made the classification of CMT even more challenging. Despite so many different mutated genes, the majority of CMT forms share a similar clinical phenotype, and due to this phenotypic homogeneity, genetic testing in CMT is increasingly being performed through the use of NGS panels. The majority of patients still have a mutation in one the four most common genes (PMP22 duplication-CMT1A, MPZ-CMT1B, GJB1-CMTX1, and MFN2-CMT2A). This chapter focuses primarily on these four forms and their potential therapeutic approaches.
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Affiliation(s)
- Chiara Pisciotta
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Michael E Shy
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
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6
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Cristiano L. The pseudogenes of eukaryotic translation elongation factors (EEFs): Role in cancer and other human diseases. Genes Dis 2022; 9:941-958. [PMID: 35685457 PMCID: PMC9170609 DOI: 10.1016/j.gendis.2021.03.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
The eukaryotic translation elongation factors (EEFs), i.e. EEF1A1, EEF1A2, EEF1B2, EEF1D, EEF1G, EEF1E1 and EEF2, are coding-genes that play a central role in the elongation step of translation but are often altered in cancer. Less investigated are their pseudogenes. Recently, it was demonstrated that pseudogenes have a key regulatory role in the cell, especially via non-coding RNAs, and that the aberrant expression of ncRNAs has an important role in cancer development and progression. The present review paper, for the first time, collects all that published about the EEFs pseudogenes to create a base for future investigations. For most of them, the studies are in their infancy, while for others the studies suggest their involvement in normal cell physiology but also in various human diseases. However, more investigations are needed to understand their functions in both normal and cancer cells and to define which can be useful biomarkers or therapeutic targets.
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Abstract
Demyelinating forms of Charcot-Marie-Tooth disease (CMT) are genetically and phenotypically heterogeneous and result from highly diverse biological mechanisms including gain of function (including dominant negative effects) and loss of function. While no definitive treatment is currently available, rapid advances in defining the pathomechanisms of demyelinating CMT have led to promising pre-clinical studies, as well as emerging clinical trials. Especially promising are the recently completed pre-clinical genetic therapy studies in PMP-22, GJB1, and SH3TC2-associated neuropathies, particularly given the success of similar approaches in humans with spinal muscular atrophy and transthyretin familial polyneuropathy. This article focuses on neuropathies related to mutations in PMP-22, MPZ, and GJB1, which together comprise the most common forms of demyelinating CMT, as well as on select rarer forms for which promising treatment targets have been identified. Clinical characteristics and pathomechanisms are reviewed in detail, with emphasis on therapeutically targetable biological pathways. Also discussed are the challenges facing the CMT research community in its efforts to advance the rapidly evolving biological insights to effective clinical trials. These considerations include the limitations of currently available animal models, the need for personalized medicine approaches/allele-specific interventions for select forms of demyelinating CMT, and the increasing demand for optimal clinical outcome assessments and objective biomarkers.
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Affiliation(s)
- Vera Fridman
- Department of Neurology, University of Colorado Anschutz Medical Campus, 12631 E 17th Avenue, Mailstop B185, Room 5113C, Aurora, CO, 80045, USA.
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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8
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Stavrou M, Sargiannidou I, Georgiou E, Kagiava A, Kleopa KA. Emerging Therapies for Charcot-Marie-Tooth Inherited Neuropathies. Int J Mol Sci 2021; 22:6048. [PMID: 34205075 PMCID: PMC8199910 DOI: 10.3390/ijms22116048] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/29/2021] [Accepted: 05/31/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited neuropathies known as Charcot-Marie-Tooth (CMT) disease are genetically heterogeneous disorders affecting the peripheral nerves, causing significant and slowly progressive disability over the lifespan. The discovery of their diverse molecular genetic mechanisms over the past three decades has provided the basis for developing a wide range of therapeutics, leading to an exciting era of finding treatments for this, until now, incurable group of diseases. Many treatment approaches, including gene silencing and gene replacement therapies, as well as small molecule treatments are currently in preclinical testing while several have also reached clinical trial stage. Some of the treatment approaches are disease-specific targeted to the unique disease mechanism of each CMT form, while other therapeutics target common pathways shared by several or all CMT types. As promising treatments reach the stage of clinical translation, optimal outcome measures, novel biomarkers and appropriate trial designs are crucial in order to facilitate successful testing and validation of novel treatments for CMT patients.
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Affiliation(s)
- Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Elena Georgiou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
- Center for Neuromuscular Diseases, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus
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Wang H, Gao Y, Guan J, Lan L, Yang J, Xiong W, Zhao C, Xie L, Yu L, Wang D, Wang Q. Phenotypic Heterogeneity of Post-lingual and/or Milder Hearing Loss for the Patients With the GJB2 c.235delC Homozygous Mutation. Front Cell Dev Biol 2021; 9:647240. [PMID: 33718389 PMCID: PMC7953049 DOI: 10.3389/fcell.2021.647240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/08/2021] [Indexed: 01/01/2023] Open
Abstract
Objective To report the phenotypic heterogeneity of GJB2 c.235delC homozygotes associated with post-lingual and/or milder hearing loss, and explore the possible mechanism of these unconditional phenotypes. Methods Mutation screening of GJB2 was performed on all ascertained members from Family 1006983 and three sporadic patients by polymerase chain reaction (PCR) amplification and Sanger sequencing. Next generation sequencing (NGS) was successively performed on some of the affected members and normal controls from Family 1006983 to explore additional possible genetic codes. Reverse transcriptase–quantitative PCR was conducted to test the expression of Connexin30. Results We identified a Chinese autosomal recessive hearing loss family with the GJB2 c.235delC homozygous mutation, affected members from which had post-lingual moderate to profound hearing impairment, and three sporadic patients with post-lingual moderate hearing impairment, instead of congenital profound hearing loss. NGS showed no other particular variants. Overexpression of Connexin30 in some of these cases was verified. Conclusion Post-lingual and/or moderate hearing impairment phenotypes of GJB2 c.235delC homozygotes are not the most common phenotype, revealing the heterogeneity of GJB2 pathogenic mutations. To determine the possible mechanism that rescues part of the hearing or postpones onset age of these cases, more cases are required to confirm both Connexin30 overexpression and the existence of modifier genes.
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Affiliation(s)
- Hongyang Wang
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Yun Gao
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Jing Guan
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Lan Lan
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Ju Yang
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Wenping Xiong
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Cui Zhao
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Linyi Xie
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Lan Yu
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Dayong Wang
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Qiuju Wang
- College of Otolaryngology, Head and Neck Surgery, Chinese People's Liberation Army (PLA) Institute of Otolaryngology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
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Genetic mechanisms of peripheral nerve disease. Neurosci Lett 2020; 742:135357. [PMID: 33249104 DOI: 10.1016/j.neulet.2020.135357] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022]
Abstract
Peripheral neuropathies of genetic etiology are a very diverse group of disorders manifesting either as non-syndromic inherited neuropathies without significant manifestations outside the peripheral nervous system, or as part of a systemic or syndromic genetic disorder. The former and most frequent group is collectively known as Charcot-Marie-Tooth disease (CMT), with prevalence as high as 1:2,500 world-wide, and has proven to be genetically highly heterogeneous. More than 100 different genes have been identified so far to cause various CMT forms, following all possible inheritance patterns. CMT causative genes belong to several common functional pathways that are essential for the integrity of the peripheral nerve. Their discovery has provided insights into the normal biology of axons and myelinating cells, and has highlighted the molecular mechanisms including both loss of function and gain of function effects, leading to peripheral nerve degeneration. Demyelinating neuropathies result from dysfunction of genes primarily affecting myelinating Schwann cells, while axonal neuropathies are caused by genes affecting mostly neurons and their long axons. Furthermore, mutation in genes expressed outside the nervous system, as in the case of inherited amyloid neuropathies, may cause peripheral neuropathy resulting from accumulation of β-structured amyloid fibrils in peripheral nerves in addition to various organs. Increasing insights into the molecular-genetic mechanisms have revealed potential therapeutic targets. These will enable the development of novel therapeutics for genetic neuropathies that remain, in their majority, without effective treatment.
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11
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Mroczek M, Sanchez MG. Genetic modifiers and phenotypic variability in neuromuscular disorders. J Appl Genet 2020; 61:547-558. [PMID: 32918245 DOI: 10.1007/s13353-020-00580-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/31/2020] [Accepted: 09/06/2020] [Indexed: 12/13/2022]
Abstract
Neuromuscular disorders are mostly rare diseases with autosomal dominant, recessive, or X-linked inheritance. Interestingly, among patients carrying the same mutations, a range of phenotypic severity is reported. This phenotypic variability in neuromuscular disorders is still not fully understood. This review will focus on genetic modifiers and will briefly describe metabolic pathways, in which they are involved. Genetic modifiers are variants in the same or other genes that modulate the phenotype. Proteins encoded by genetic modifiers in neuromuscular diseases are taking part in different metabolic processes, most commonly in inflammation, growth and regeneration, endoplasmic reticulum metabolism, and cytoskeletal activities. Recent advances in omics technologies, development of computational algorithms, and establishing large international consortia intensified discovery sped up investigation of genetic modifiers. As more individuals affected by neuromuscular disorders are tested, it is often suggested that classic models of genetic causation cannot explain phenotypic variability. There is a growing interest in their discovery and identifying shared metabolic pathways can contribute to design targeted therapies. We provide an update on variants acting as genetic modifiers in neuromuscular disorders and strategies used for their discovery.
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Affiliation(s)
- Magdalena Mroczek
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
| | - Maria Gabriela Sanchez
- Molecular Biology Department, Simon Bolivar University, Sartenejas Valley, Caracas, Venezuela
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12
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Visigalli D, Capodivento G, Basit A, Fernández R, Hamid Z, Pencová B, Gemelli C, Marubbi D, Pastorino C, Luoma AM, Riekel C, Kirschner DA, Schenone A, Fernández JA, Armirotti A, Nobbio L. Exploiting Sphingo- and Glycerophospholipid Impairment to Select Effective Drugs and Biomarkers for CMT1A. Front Neurol 2020; 11:903. [PMID: 32982928 PMCID: PMC7477391 DOI: 10.3389/fneur.2020.00903] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 07/14/2020] [Indexed: 01/12/2023] Open
Abstract
In Charcot-Marie-Tooth type 1A (CMT1A), Schwann cells exhibit a preponderant transcriptional deficiency of genes involved in lipid biosynthesis. This perturbed lipid metabolism affects the peripheral nerve physiology and the structure of peripheral myelin. Nevertheless, the identification and functional characterization of the lipid species mainly responsible for CMT1A myelin impairment currently lack. This is critical in the pathogenesis of the neuropathy since lipids are many and complex molecules which play essential roles in the cell, including the structural components of cellular membranes, cell signaling, and membrane trafficking. Moreover, lipids themselves are able to modify gene transcription, thereby affecting the genotype-phenotype correlation of well-defined inherited diseases, including CMT1A. Here we report for the first time a comprehensive lipid profiling in experimental and human CMT1A, demonstrating a previously unknown specific alteration of sphingolipid (SP) and glycerophospholipid (GP) metabolism. Notably, SP, and GP changes even emerge in biological fluids of CMT1A rat and human patients, implying a systemic metabolic dysfunction for these specific lipid classes. Actually, SP and GP are not merely reduced; their expression is instead aberrant, contributing to the ultrastructural abnormalities that we detailed by X-ray diffraction in rat and human internode myelin. The modulation of SP and GP pathways in myelinating dorsal root ganglia cultures clearly sustains this issue. In fact, just selected molecules interacting with these pathways are able to modify the altered geometric parameters of CMT1A myelinated fibers. Overall, we propose to exploit the present SP and GP metabolism impairment to select effective drugs and validate a set of reliable biomarkers, which remain a challenge in CMT1A neuropathy.
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Affiliation(s)
- Davide Visigalli
- DINOGMI, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Clinica Neurologica, Genoa, Italy
| | - Giovanna Capodivento
- DINOGMI, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Clinica Neurologica, Genoa, Italy
| | - Abdul Basit
- Analytical Chemistry Lab, Fondazione Istituto Italiano di Tecnologia, Genoa, Italy
| | - Roberto Fernández
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country, Leioa, Spain
| | - Zeeshan Hamid
- Analytical Chemistry Lab, Fondazione Istituto Italiano di Tecnologia, Genoa, Italy
| | - Barbora Pencová
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country, Leioa, Spain
| | - Chiara Gemelli
- DINOGMI, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Clinica Neurologica, Genoa, Italy
| | - Daniela Marubbi
- DIMES, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Oncologia Cellulare Genoa, Genoa, Italy
| | - Cecilia Pastorino
- DINOGMI, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Clinica Neurologica, Genoa, Italy
| | - Adrienne M Luoma
- Department of Biology, Boston College, Boston, MA, United States
| | | | | | - Angelo Schenone
- DINOGMI, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Clinica Neurologica, Genoa, Italy
| | - José A Fernández
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country, Leioa, Spain
| | - Andrea Armirotti
- Analytical Chemistry Lab, Fondazione Istituto Italiano di Tecnologia, Genoa, Italy
| | - Lucilla Nobbio
- DINOGMI, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico S. Martino, UO Clinica Neurologica, Genoa, Italy
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13
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Lee AJ, Nam DE, Choi YJ, Noh SW, Nam SH, Lee HJ, Kim SJ, Song GJ, Choi BO, Chung KW. Paternal gender specificity and mild phenotypes in Charcot-Marie-Tooth type 1A patients with de novo 17p12 rearrangements. Mol Genet Genomic Med 2020; 8:e1380. [PMID: 32648354 PMCID: PMC7507087 DOI: 10.1002/mgg3.1380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 05/27/2020] [Accepted: 05/31/2020] [Indexed: 01/06/2023] Open
Abstract
Background Charcot–Marie–Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are developed by duplication and deletion of the 17p12 (PMP22) region, respectively. Methods De novo rates were determined in 211 CMT1A or HNPP trio families, and then, analyzed gender‐specific genetic features and clinical phenotypes of the de novo cases. Results This study identified 40 de novo cases (19.0%). Paternal origin was highly frequent compared to maternal origin (p = .005). Most de novo CMT1A rearrangements occurred between non‐sister chromatids (p = .003), but it was interesting that three of the four sister chromatids exchange cases were observed in the less frequent maternal origin. Paternal ages at the affected child births were slightly higher in the de novo CMT1A group than in the non‐de novo CMT1A control group (p = .0004). For the disability score of CMTNS, the de novo CMT1A group had a slightly lower value compared to the control group (p = .005). Electrophysiological studies showed no significant differences between the two groups. Conclusion This study suggests that de novo CMT1A patients tend to have milder symptoms and that the paternal ages at child births in the de novo group are higher than those of the non‐de novo group.
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Affiliation(s)
- Ah J Lee
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Da E Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Yu J Choi
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Seung W Noh
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Soo H Nam
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
| | - Hye J Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Seung J Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Gyun J Song
- Department of Medical Science, Institute for Bio-Medical Convergence, Catholic Kwandong University, International St. Mary's Hospital, Incheon, Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ki W Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
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14
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Liu X, Duan X, Zhang Y, Fan D. Clinical and Genetic Diversity of PMP22 Mutations in a Large Cohort of Chinese Patients With Charcot-Marie-Tooth Disease. Front Neurol 2020; 11:630. [PMID: 32719652 PMCID: PMC7347970 DOI: 10.3389/fneur.2020.00630] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 05/28/2020] [Indexed: 12/16/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous group of inherited neuropathies. The purpose of this study is to identify the clinical and genetic diversity of peripheral myelin protein 22 (PMP22) in Chinese patients with CMT disease and evaluate their correlations with the clinical manifestations. Using the multiplex ligation-dependent probe amplification (MLPA) technique and Sanger sequencing of PMP22 in a cohort of 465 Chinese families between 2007 and 2019, we identified 137 pedigrees with PMP22 duplications (29.5%), 26 pedigrees with PMP22 deletions (5.6%), and 10 pedigrees with point mutations (2.2%). By comparing our data with the results from other CMT centers in China, we estimate that the frequency of PMP22 mutation in mainland China is ~23.3% (261/1120). We confirmed de novo mutations in 40% (4/10) of PMP22 point mutations. We have also identified two severely affected patients who are compound heterozygotes for recessive PMP22 mutations (novel mutation c.320-1 G>A and R157W mutation) and a 1.5 Mb deletion in 17p11.2-p12, suggesting that c.320-1 G>A might be another recessive allele contributing to DSS in addition to the T118M and R157W mutations. A de novo mutation of S79P in PMP22 was also identified concomitantly with the R94W mutation in mitofusin2 (MFN2). Our study highlights the phenotypic variability associated with PMP22 mutations in mainland China. The results provide valuable insights into the current strategy of genetic testing for CMT disease. NGS technology has increased the potential for efficient detection of variants of unknown significance (VUS) and concurrent causative genes. Greater cooperation between neurologists and molecular biologists is needed in future investigations.
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Affiliation(s)
- Xiaoxuan Liu
- Department of Neurology, Peking University Third Hospital, Beijing, China
| | - Xiaohui Duan
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
| | - Yingshuang Zhang
- Department of Neurology, Peking University Third Hospital, Beijing, China
| | - Dongsheng Fan
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
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