Abstract
We studied the cellular distribution of both deleted (Δ) and wild-type (wt) mitochondrial DNAs (mtDNAs) in 'normal' and respiration-deficient muscle fibers from four patients with mitochondrial myopathy. PCR-based methods were used to quantitate both relative and absolute amounts of Δ- and wt-mtDNAs in microdissected fiber segments. Although Δ-mtDNAs were present in normal fibers (31% ± 26), their percentages were much higher in affected fibers (95% ± 2). Absolute levels of Δ-mtDNA were also increased in affected fibers, whereas levels of wt-mtDNA were significantly reduced in these fibers. These results indicate that a threshold ratio of Δ-/wt-mtDNA must be achieved before an impairment of respiration is observed in muscle. Moreover, the marked reduction in wt-mtDNA observed in affected fibers suggests that absolute amounts of mtDNA may play a role in the pathogenesis of mitochondrial myopathies.
Original language | English (US) |
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Pages (from-to) | 13-19 |
Number of pages | 7 |
Journal | Human molecular genetics |
Volume | 3 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 1994 |
ASJC Scopus subject areas
- Molecular Biology
- Genetics
- Genetics(clinical)