[Nuclear transfer to prevent transmission of mtDNA disorders: where are we?].

The recent birth from a mitochondrial DNA mutation carrier of a child, conceived after transfer in a donor oocyte of the meiotic spindle, taken from the maternal oocyte, revived the debate on the safety of these procedures. The doubts concern mainly the possibility of genetic reversion, the uncertainties about potential disturbances of the dialogue between nuclear and mitochondrial genomes and the side effects of a heteroplasmic state induced by these techniques. The possibility to expand nuclear transfer applications to patients experiencing in vitro fertilization failure, urges us to answer these questions rapidly.