Scientists in the Netherlands achieved a significant milestone by utilizing mitochondrial base editing to directly correct deleterious mutations in human cells. Using a double-stranded DNA cytosine base editor, the team precisely converted cytosine to thymine in mitochondrial DNA without causing double-stranded breaks, overcoming historical challenges posed by mitochondrial membrane impermeability and lack of RNA pathways for classic genome editing systems. This advance offers promising therapeutic potential for treating mitochondrial diseases, which have been difficult to target given the unique biology of mitochondrial genetics.