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Lookup NU author(s): Dr Yi NgORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
© 2024 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.Background and purpose: Late-onset mitochondrial disorders are diagnostically challenging with significant heterogeneity in disease presentation. A case is reported of a 67-year-old gentleman who presented with a 3-month history of seizures, recurrent encephalopathy, ataxia and weight loss, preceded by recent initiation of haemodialysis for end-stage chronic kidney disease. Methods: Extensive work-up including serological, cerebrospinal fluid, magnetic resonance imaging and electroencephalography was performed. Whole exome sequencing and muscle biopsy confirmed the diagnosis. Results: Magnetic resonance imaging brain demonstrated a single non-enhancing T2 fluid attenuated inversion recovery hyperintense cortical/subcortical signal change in the right temporal lobe and cerebellar atrophy. Given the subacute presentation of uncertain aetiology, he was empirically treated for autoimmune/paraneoplastic encephalitis. Despite radiological resolution of the cortical abnormality 2 weeks later, there was no clinical improvement. Further collateral history unveiled a mildly ataxic gait and longstanding hearing loss suggestive of a genetic cause. Whole exome sequencing revealed a likely pathogenic, heteroplasmic mitochondrial DNA variant in the MT-TV gene, m.1659T>C, present at higher levels of heteroplasmy in muscle (91%) compared to other mitotic tissues. A high fat/protein diet and multivitamins including co-enzyme Q10 were commenced. Treatment of the nutritional deficiency and avoidance of intermittent fasting due to unreliable oral intake secondary to encephalopathy probably contributed to the clinical improvement seen over the ensuing few months, with resolution of his encephalopathy and return to his baseline gait and weight. Conclusion: An adult case is reported with an acute neurological presentation mimicking encephalitis, caused by a heteroplasmic m.1659T>C MT-TV variant, previously reported once in a child who displayed a different clinical phenotype.
Author(s): Joyce E, Ali M, Richard G, Kelly S, Martin F, Conlon PJ, Whelehan A, Ng YS, Lefter S
Publication type: Article
Publication status: Published
Journal: European Journal of Neurology
Year: 2024
Online publication date: 08/07/2024
Acceptance date: 20/06/2024
Date deposited: 16/07/2024
ISSN (print): 1351-5101
ISSN (electronic): 1468-1331
Publisher: John Wiley and Sons Inc
URL: https://doi.org/10.1111/ene.16405
DOI: 10.1111/ene.16405
Data Access Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request
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