Rhabdomyolysis due to mtDNA pathogenic variants: Report of a subject with a novel MT-CO3 variant and review of the literature.

Rhabdomyolysis can be due to mitochondrial myopathy, but mitochondrial DNA (mtDNA) pathogenic variants are often overlooked in standard genetic panels. We report a 41-year-old woman with recurrent rhabdomyolysis due to a novel MT-CO3 variant. Muscle biopsy showed cytochrome c oxidase-negative fibers that segregated with high heteroplasmic load on single-fiber. We additionally review previously reported mtDNA variants associated with rhabdomyolysis, highlighting the diagnostic relevance of mtDNA analysis and tissue-specific testing in unexplained rhabdomyolysis.