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Braz LP, Ng YS, Gorman GS, Schaefer AM, McFarland R, Taylor RW, Turnbull DM, Whittaker RG. Neuromuscular Junction Abnormalities in Mitochondrial Disease: An Observational Cohort Study. Neurol Clin Pract 2019; 11:97-104. [PMID: 33842062 PMCID: PMC8032443 DOI: 10.1212/cpj.0000000000000795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objective To determine the prevalence of neuromuscular junction (NMJ) abnormalities in patients with mitochondrial disease. Methods Eighty patients with genetically proven mitochondrial disease were recruited from a national center for mitochondrial disease in the United Kingdom. Participants underwent detailed clinical and neurophysiologic testing including single-fiber electromyography. Results The overall prevalence of neuromuscular transmission defects was 25.6%. The highest prevalence was in patients with pathogenic dominant RRM2B variants (50%), but abnormalities were found in a wide range of mitochondrial genotypes. The presence of NMJ abnormalities was strongly associated with coexistent myopathy, but not with neuropathy. Furthermore, 15% of patients with NMJ abnormality had no evidence of either myopathy or neuropathy. Conclusions NMJ transmission defects are common in mitochondrial disease. In some patients, NMJ dysfunction occurs in the absence of obvious pre- or post-synaptic pathology, suggesting that the NMJ may be specifically affected.
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Affiliation(s)
- Luis P Braz
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yi Shiau Ng
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gráinne S Gorman
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew M Schaefer
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert McFarland
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert W Taylor
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Doug M Turnbull
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Roger G Whittaker
- Department of Neurology (LPB), Centro Hospitalar Universitário de São João, Porto, Portugal; and Wellcome Centre for Mitochondrial Research (YSN, GSG, AMS, RM, RWT, DMT), Translational and Clinical Research Institute (RGW), Newcastle University, Newcastle upon Tyne, United Kingdom
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