Clinical and ethical implications of mitochondrial gene transfer

Inherited diseases caused by mitochondrial gene (mtDNA) mutations affect at least 1 in 5000-10 000 children and are associated with severe clinical symptoms. Novel reproductive techniques designed to replace mutated mtDNA in oocytes or early embryos have been proposed to prevent transmission of disease from parents to their children. Here we review the efficacy and safety of these approaches and their associated ethical and regulatory issues.