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Muscle structural changes in mitochondrial myopathy relate to genotype
David B Olsen1, Annika R Langkilde, Mette C Ørngreen
1Dept. of Neurology and The Copenhagen Muscle Research Center, National University Hospital, Rigshospitalet, Copenhagen, Denmark. d.benee@gmx.net
Journal of Neurology
|December 4, 2003
Summary
Mitochondrial myopathy (MM) can cause muscle structure changes resembling muscular dystrophy, particularly with high mtDNA mutation loads. These dystrophic-like changes are linked to specific genetic mutations in mitochondrial DNA.
Area of Science:
- Neurology
- Genetics
- Pathology
Background:
- Mitochondrial myopathy (MM) is known for cellular morphological changes.
- Gross structural muscle changes, like fat infiltration and fiber size variation, are typically associated with muscular dystrophies, not MM.
Purpose of the Study:
- To investigate gross and microscopic muscle morphology in MM patients.
- To compare muscle morphology in MM patients with muscular dystrophy patients and healthy subjects.
- To determine the relationship between genotype and dystrophic-like muscle changes in MM.
Main Methods:
- Muscle biopsy and MRI of thigh muscles were performed on 16 MM patients.
- Findings were compared with those from muscular dystrophy patients and healthy controls.
Main Results:
- Dystrophic-like muscle architecture changes were observed in MM patients with high mutation loads for large-scale mtDNA deletions.
- These changes were absent in MM patients with the 3243A-->G mtDNA point mutation.
- One MM patient with a unique sporadic mutation also showed dystrophic changes.
Conclusions:
- Morphological changes in MM muscles are common and can mimic muscular dystrophy.
- The development of dystrophic-like changes in MM is strongly related to the specific genotype and mutation load of mitochondrial DNA.