Mitochondrial diseases are caused by mutations in the genes for crucial sub-cellular components, the mitochondria; such mutations are common, but they may more rarely cause very severe and progressive disease.
Prospects for preventing transmission of mitochondrial disease have been building for some time (see previous news); now UK Secretary of State for Health Andrew Lansley has requested that the HFEA report expert views on ’the effectiveness and safety of mitochondrial transfer’, a cloning technique combined with in vitro fertilisation.
It involves removing the nucleus (containing almost all the DNA) from a fertilised egg cell and transplanting it into a healthy donor fertilised egg cell from which the nucleus has been removed. The resulting embryo derives a small amount of mitochondrial DNA from the donor, as well as that from the natural parents.
Implantation of such embryos is not currently permitted in the UK but Parliament could reverse this ban, though licences to perform the procedure would still be required. The HFEA panel will report by mid-April and their findings will be taken into consideration by the Department of Health in deciding whether or not a public consultation on the possible introduction of mitochondrial transfer in the UK is warranted.
Comment: If there is sufficient evidence of safety and efficacy, there is a clear regulatory process for introduction of mitochondrial transfer. Public (and hence parliamentary) opinion of the technique will also play a role, however, and taking views into account will be important in determining public acceptability.