Genome Editing Tools to Increase the Efficacy of Mitochondrial Donation

Abstract

Mitochondrial donation (MD) aims to prevent transmission of mtDNA disease by transplanting the nuclear genome from an affected woman’s egg to an enucleated egg from an unaffected donor. The nuclear DNA is transplanted in a karyoplast, which upon fusion with the enucleated donor egg, introduces a small amount of perinuclear mitochondria resulting in heteroplasmy for maternal mtDNA. Under optimal conditions, this accounts for <2% of the mtDNA content of MD embryos. Despite this, [Formula: see text]20% of embryonic stem (ES) cell lines derived from MD embryos exhibit complete reversion to the maternal mitochondrial genome and elevated levels (40–60%) have recently been reported in a baby born following MD treatment for infertility. Thus, currently available MR treatments are regarded as risk reduction, rather than prevention strategies. A major focus of our ongoing research is to bridge this gap by developing techniques to minimise maternal mtDNA in MD embryos. I will present our recent findings from these investigations.