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Mitochondrial DNA m.3243A > G heteroplasmy affects multiple aging phenotypes and risk of mortality

Gregory J Tranah1, Shana M Katzman2, Kevin Lauterjung3

  • 1California Pacific Medical Center Research Institute, San Francisco, CA, 94107, USA. gtranah@sfcc-cpmc.net.

Scientific Reports
|August 10, 2018
PubMed

Insights

Elevated mitochondrial DNA (mtDNA) m.3243A>G mutation heteroplasmy in older adults is linked to declines in physical and cognitive function. This genetic mutation also increases the risk of mortality from all causes, dementia, and stroke.

Area of Science:

  • Genetics
  • Gerontology
  • Mitochondrial Biology

Background:

  • Mitochondrial DNA (mtDNA) exists in multiple copies within cells and can present as a mix of normal and mutated forms, a condition known as heteroplasmy.
  • The specific mtDNA mutation m.3243A>G, when present at elevated levels, is associated with a range of serious health impairments, including neurological, metabolic, and cardiopulmonary issues.

Purpose of the Study:

  • To investigate the association between leukocyte mtDNA m.3243A>G heteroplasmy and age-related functional decline and mortality in an elderly population.
  • To determine if the burden of this specific mtDNA mutation correlates with measures of physical strength, cognitive ability, metabolic health, and cardiovascular function.

Main Methods:

  • Analysis of leukocyte mtDNA m.3243A>G heteroplasmy in 789 participants from the Health, Aging, and Body Composition Study.
  • Measurement of mutation burden, ranging from 0-19%, and correlation with various functional assessments and mortality data.

Main Results:

  • Elevated m.3243A>G heteroplasmy was significantly associated with reduced strength, cognitive, metabolic, and cardiovascular functioning.
  • Participants in the highest tertiles of m.3243A>G heteroplasmy exhibited a significantly increased risk of all-cause, dementia, and stroke mortality.

Conclusions:

  • The accumulation of the m.3243A>G mtDNA mutation contributes to multiple aging-related outcomes, suggesting a link between genetic damage and the aging process.
  • Mitochondrial DNA damage, specifically the m.3243A>G mutation, may be a contributing factor to several diseases commonly associated with aging.

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