heteroplasmy

genetics

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July 16, 2026

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Heteroplasmy refers to the presence of more than one type of mitochondrial DNA (mtDNA) within a cell or organism. Mitochondria are organelles responsible for generating most of a cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.12

Mitochondrial DNA is inherited maternally, meaning it comes from the mother's egg cell. In a cell with heteroplasmy, there can be a mix of normal and mutated mtDNA. The severity of any resulting mitochondrial disorder often depends on the proportion of normal versus mutated mtDNA. This condition is distinct from nuclear DNA inheritance, which follows Mendelian patterns.13

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human genetic disease
Mitochondrial DNA mutations
…reflect the combined effects of heteroplasmy (i.e., mixed populations of both normal and mutant mitochondrial DNA in a single cell) and other confounding genetic or environmental factors. There are close to 50 mitochondrial genetic diseases currently known.
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…reflect the combined effects of heteroplasmy (i.e., mixed populations of both normal and mutant mitochondrial DNA in a single cell) and other confounding genetic or environmental factors. There are close to 50 mitochondrial genetic diseases currently known.
Read More

three-parent baby
The biological basis of mitochondrial replacement
…greatest for women with high heteroplasmy—women whose total mtDNA content in affected cells or tissues is made up of between 60 and 90 percent mutated mtDNA, the threshold at which mitochondrial disease becomes apparent clinically. However, even women with low heteroplasmy and who are therefore asymptomatic are at risk of…
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…greatest for women with high heteroplasmy—women whose total mtDNA content in affected cells or tissues is made up of between 60 and 90 percent mutated mtDNA, the threshold at which mitochondrial disease becomes apparent clinically. However, even women with low heteroplasmy and who are therefore asymptomatic are at risk of…
Read More