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Xu IRL, Danzi MC, Ruiz A, Raposo J, De Jesus YA, Reilly MM, Cortese A, Shy ME, Scherer SS, Herrmann DN, Fridman V, Baets J, Saporta M, Seyedsadjadi R, Stojkovic T, Claeys KG, Patel P, Feely S, Rebelo AP, 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. [PMID: 38581130 DOI: 10.1111/jns.12621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 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, Florida, 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, Florida, 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, Florida, 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, Florida, 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, Florida, USA
| | - Mary M Reilly
- Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square, London, UK
| | - Andrea Cortese
- Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square, London, UK
- Department of Brain and Behaviour Sciences, University of Pavia, Pavia, Italy
| | - 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, Pennsylvania, USA
| | - David N Herrmann
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Vera Fridman
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 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, Miami, Florida, USA
| | - Reza Seyedsadjadi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tanya Stojkovic
- APHP, Neuromuscular Diseases Reference Center, Pitié-Salpêtrière Hospital, 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, Pennsylvania, USA
| | - Shawna Feely
- Department of Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Adriana P 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, Florida, 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, Florida, 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, Florida, USA
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Kitani-Morii F, Noto YI, Tsuji Y, Shiga K, Mizuta I, Nakagawa M, Mizuno T. Rate of Changes in CMT Neuropathy and Examination Scores in Japanese Adult CMT1A Patients. Front Neurol 2020; 11:626. [PMID: 32765395 PMCID: PMC7378731 DOI: 10.3389/fneur.2020.00626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/28/2020] [Indexed: 12/20/2022] Open
Abstract
Introduction: We aimed to clarify when adult patients with Charcot-Marie-Tooth disease type 1A (CMT1A), especially those diagnosed at middle or advanced ages, first showed symptoms and whether the rate of disease progression is accelerated by aging. Methods: Medical records of CMT1A outpatients between 2012 and 2019 were reviewed. The age at diagnosis, age when symptoms first appeared, and rate of disease progression, assessed based on clinical outcome measures including the CMT Neuropathy Score (CMTNS), Rasch-modified CMTNS (CMTNS-R), CMT Examination Score (CMTES), and Rasch-modified CMTES (CMTES-R) were analyzed. Results: Among 45 adult CMT1A patients, 42% had been diagnosed after 50 years of age, whereas 91% of all patients had exhibited some CMT-related symptoms before 20 years of age. The annual increase of all clinical outcome measures did not differ between patients under and over 50 years. Even when limited to patients whose initial CMTES-R showed mild to moderate severity, the rate of change in CMTES-R did not differ between the two age groups (the annual mean ± standard deviation, under 50 years: 1.1 ± 1.0, and over 50 years: 0.9 ± 1.1, p = 0.68). To determine whether patients with disabilities at a young age have a higher deterioration rate, they were classified into three groups according to their current age and age at diagnosis: patients under 50 years of age, patients over 50 years of age but diagnosed before 50, and patients diagnosed after 50 years of age. The mean annual increase of all clinical outcome measures, however, did not differ among these groups (CMTES-R: 1.03 ± 1.01 vs. 0.94 ± 1.57 vs. 0.81 ± 0.88, respectively, p = 0.87). Discussion: CMT1A patients develop symptoms in childhood and adolescence even if such symptoms are not noticeable until reaching an advanced age. Deterioration rates of clinical outcome measures are constant irrespective of the age in their adulthood, although we cannot rule out the limitation that the difference did not reach significance because of the small number of patients. Being aware of the existence of a considerable number of undiagnosed CMT patients will help promote the avoidance of inadequate medication.
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Affiliation(s)
- Fukiko Kitani-Morii
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yu-Ichi Noto
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yukiko Tsuji
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kensuke Shiga
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Neurology, Matsushita Memorial Hospital, Osaka, Japan
| | - Ikuko Mizuta
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Masanori Nakagawa
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Neurology, North Medical Center, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshiki Mizuno
- Department of Neurology, Graduate School of Kyoto Prefectural University of Medicine, Kyoto, Japan
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