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Muscle MRI characteristic pattern for late-onset TK2 deficiency diagnosis

Lookup NU author(s): Roberto Fernandez-Torron, Dr ursula Moore, Dr German Moris, Dr Nuria Muelas Gomez



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2022, The Author(s). Background and objective: TK2 deficiency (TK2d) is a rare mitochondrial disorder that manifests predominantly as a progressive myopathy with a broad spectrum of severity and age of onset. The rate of progression is variable, and the prognosis is poor due to early and severe respiratory involvement. Early and accurate diagnosis is particularly important since a specific treatment is under development. This study aims to evaluate the diagnostic value of lower limb muscle MRI in adult patients with TK2d. Methods: We studied a cohort of 45 genetically confirmed patients with mitochondrial myopathy (16 with mutations in TK2, 9 with mutations in other nuclear genes involved in mitochondrial DNA [mtDNA] synthesis or maintenance, 10 with single mtDNA deletions, and 10 with point mtDNA mutations) to analyze the imaging pattern of fat replacement in lower limb muscles. We compared the identified pattern in patients with TK2d with the MRI pattern of other non-mitochondrial genetic myopathies that share similar clinical characteristics. Results: We found a consistent lower limb muscle MRI pattern in patients with TK2d characterized by involvement of the gluteus maximus, gastrocnemius medialis, and sartorius muscles. The identified pattern in TK2 patients differs from the known radiological involvement of other resembling muscle dystrophies that share clinical features. Conclusions: By analyzing the largest cohort of muscle MRI from patients with mitochondrial myopathies studied to date, we identified a characteristic and specific radiological pattern of muscle involvement in patients with TK2d that could be useful to speed up its diagnosis.

Publication metadata

Author(s): Dominguez-Gonzalez C, Fernandez-Torron R, Moore U, de Fuenmayor-Fernandez de la Hoz CP, Velez-Gomez B, Cabezas JA, Alonso-Perez J, Gonzalez-Mera L, Olive M, Garcia-Garcia J, Moris G, Leon Hernandez JC, Muelas N, Servian-Morilla E, Martin MA, Diaz-Manera J, Paradas C

Publication type: Article

Publication status: Published

Journal: Journal of Neurology

Year: 2022

Volume: 269

Pages: 3550-3562

Print publication date: 01/07/2022

Online publication date: 14/03/2022

Acceptance date: 30/12/2021

Date deposited: 29/03/2022

ISSN (print): 0340-5354

ISSN (electronic): 1432-1459

Publisher: Springer Nature


DOI: 10.1007/s00415-021-10957-0


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