Assisted Reproductive Technologies: The Potential to Prevent the Transmission of Mutant mtDNA from One Generation to the Next

Mammalian cells contain multiple identical copies of mitochondrial DNA (mtDNA) that encode genes involved in the production of ATP through the process of oxidative phosphorylation (OXPHOS). Mutations and deletions to mtDNA produce novel sequence variants, resulting in heteroplasmic mixing of mutant and wild-type molecules, which may culminate in a variety of severely debilitating and lethal multi-systemic diseases. The maternal inheritance of mtDNA is a strictly regulated process and presents a complex reproductive situation, as there are currently no proven clinical strategies available to prevent the transmission of mutant mtDNA from the mother to her offspring and to subsequent generations. Furthermore, the segregation of mtDNA during development randomly alters the mutant loading within embryonic tissues, limiting the possibility to safely predict the probability of disease manifestation. Despite these limitations, a patient may undergo an assisted reproductive program, consisting of genetic counseling and tissue sampling for biochemical and genetic screening. Encouraging studies in non-human models have developed micromanipulation approaches to reduce the transmission of mutant mtDNA between generations. However, these methodologies require further experimental validation to determine whether assisted reproductive technologies can prevent the transmission of mutant mtDNA.