Mitochondrial DNA copy number threshold in mtDNA depletion myopathy.
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.
Durham
S E
SE
Mitochondrial Research Group, The University of Newcastle upon Tyne, UK.
Bonilla
E
E
Samuels
D C
DC
DiMauro
S
S
Chinnery
P F
PF
D000328:Adult; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000235:genetics*; D005260:Female; D018628:Gene Dosage / Q000235:genetics*; D006801:Humans; D007223:Infant; D017240:Mitochondrial Myopathies / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests; D012016:Reference Values; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013937:Thymidine Kinase / Q000172:deficiency*
D004272:DNA, Mitochondrial; D013385:Succinate Dehydrogenase; D003576:Electron Transport Complex IV; C105339:thymidine kinase 2; D013937:Thymidine Kinase