A novel mitochondrial ND5 (MTND5) gene mutation giving isolated exercise intolerance
Esther Downham1, Synnøve Winterthun, Hanne Linda Nakkestad
1Department of Clinical Medicine, University of Bergen, Heukeland University Hospital, 5021 Bergen, Norway.
Neuromuscular Disorders : NMD
|April 9, 2008
Summary
A new mitochondrial DNA mutation in MTND5 causes isolated exercise intolerance. This finding highlights MTND5 as a key site for various mitochondrial diseases affecting single tissues.
Area of Science:
- Genetics
- Molecular Biology
- Neurology
Background:
- Mitochondrial DNA (mtDNA) mutations are linked to a spectrum of human diseases.
- Mutations in the MTND5 gene, encoding a subunit of respiratory chain complex I, are associated with various neurological and multi-systemic disorders.
Observation:
- A patient presented with isolated exercise intolerance.
- Genetic analysis revealed a novel, maternally inherited heteroplasmic T>C transition at position 13271 in the MTND5 gene.
Findings:
- The identified mutation affects a highly conserved base within MTND5.
- This mutation segregated with the disease phenotype, with highest levels observed in skeletal muscle fibers exhibiting abnormal mitochondrial accumulation.
- This represents the 15th identified mutation within the MTND5 gene, underscoring its significance in mitochondrial function.
Implications:
- This discovery confirms MTND5 as a crucial genetic locus for mitochondrial diseases.
- It expands the known phenotypic spectrum of MTND5 mutations to include isolated skeletal muscle exercise intolerance.
- This finding contributes to understanding genotype-phenotype correlations in mitochondrial disorders and may inform future diagnostic and therapeutic strategies.
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