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Mitochondrial cardiomyopathy with skeletal muscle myopathy caused by m.3260A > G mutation in MT-TL1 gene: a case report

Year: 2025

Type: article

Abstract: BACKGROUND: Mitochondrial myopathies are a group of rare hereditary disorders that primarily affect muscle tissue, and present with muscle weakness, fatigue, exercise intolerance, and muscle pain. A key aspect of mitochondrial myopathies is the involvement of different organ systems, such as the cardiovascular system. Various disease features, including clinical and genetic heterogeneity, pose serious difficulties in the diagnostic process. We report a case of a young adult male, who presented with findings that suggested myositis, and was diagnosed with skeletal muscle myopathy and mitochondrial cardiomyopathy, caused by a m.3260A > G variant in the MT-TL1 gene. CASE PRESENTATION: A 22-year-old Latvian Caucasian man presented with a half-year history of fatigue, weakness, heaviness in the chest, and loss of breath, as well as a swollen right lower leg for about a week. Laboratory findings revealed increased creatine phosphokinase, creatinine kinase MB, and troponin T levels. All performed autoantibody tests for autoimmune disorders were negative, and no evidence of paraneoplastic syndrome was found. During repeated stays in the hospital, the patient developed heart failure and experienced decreasing muscle strength and muscle pain throughout the whole body. Following an unsuccessful therapy with corticosteroids and later L-carnitine, addition of thiamine lead to an overall improvement in the patient's condition. Based on the family history, a genetic test was performed, which revealed a m.3260A > G variant in the MT-TL1 gene. CONCLUSION: Several factors cause the process of establishing the correct diagnosis of mitochondrial myopathies and cardiomyopathies to be challenging. The presented case aims to raise awareness of rare mitochondrial myopathies, to help clinicians speed up the diagnostic process.

Source: Journal of Medical Case Reports

DOI: 10.1186/s13256-025-05633-0

Authors: Anda Kadiša, Ritvars Vereskuns, Mihails Tarasovs, Ieva Mičule, Inna Inashkina

Institutions: Riga East University Hospital, Riga Stradiņš University, Children's Clinical University Hospital, Latvian Biomedical Research and Study Centre

Language: English

Topic: Mitochondrial Function and Pathology

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,890