Galán, Fernando, de Lavera, Isabel, Cotán, David et al. · Journal of investigative medicine high impact case reports · 2015 · DOI
This case study describes a patient who was initially diagnosed with chronic fatigue syndrome (CFS) but was later found to have a different condition called mitochondrial myopathy—a disease affecting the energy-producing structures in muscle cells. Testing showed the patient had severe deficiencies in certain components of these energy-producing structures, and genetic analysis revealed mutations inherited from the mother. The patient and family members improved significantly with high-dose vitamins B1 and B2.
This case is important because it highlights that some patients initially diagnosed with CFS may actually have undiagnosed mitochondrial disorders—a potentially treatable condition. Distinguishing between CFS and mitochondrial myopathy matters clinically because mitochondrial diseases may respond to specific interventions like high-dose B vitamins. The study underscores the need for careful diagnostic workup in CFS patients, particularly when family members share symptoms.
This single case report does not establish how frequently mitochondrial disease is misdiagnosed as CFS in the general CFS population, nor does it prove that CFS and mitochondrial myopathy are related conditions. The dramatic response to B vitamins in this family does not demonstrate that similar treatment would benefit other CFS patients or those with mitochondrial disease. Case reports generate hypotheses but cannot establish causation or population prevalence.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Galán, Fernando, de Lavera, Isabel, Cotán, David, & Sánchez-Alcázar, José A (2015). Mitochondrial Myopathy in Follow-up of a Patient With Chronic Fatigue Syndrome.. Journal of investigative medicine high impact case reports. https://doi.org/10.1177/2324709615607908
BibTeX
@article{mecfsatlas-galn-2015-mitochondrial-myopathy,
author = {Galán, Fernando and de Lavera, Isabel and Cotán, David and Sánchez-Alcázar, José A},
title = {Mitochondrial Myopathy in Follow-up of a Patient With Chronic Fatigue Syndrome.},
journal = {Journal of investigative medicine high impact case reports},
year = {2015},
doi = {10.1177/2324709615607908},
note = {PubMed: 26904705},
url = {https://www.mecfsatlas.com/evidence/galn-2015-mitochondrial-myopathy},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/galn-2015-mitochondrial-myopathy
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