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Mitochondrial DNA copy number threshold in mtDNA depletion myopathy

2005; Lippincott Williams & Wilkins; Volume: 65; Issue: 3 Linguagem: Inglês

10.1212/01.wnl.0000171861.30277.88

1526-632X

Steve E. Durham, E. Bonilla, David C. Samuels, S. DiMauro, Patrick F. Chinnery,

Glycogen Storage Diseases and Myoclonus

The authors measured the absolute amount of mitochondrial DNA (mtDNA) within single muscle fibers from two patients with thymidine kinase 2 (TK2) deficiency and two healthy controls. TK2 deficient fibers containing more than 0.01 mtDNA/microm3 had residual cytochrome c oxidase (COX) activity. This defines the minimum amount of wild-type mtDNA molecules required to maintain COX activity in skeletal muscle and provides an explanation for the mosaic histochemical pattern seen in patients with mtDNA depletion syndrome.