Scientists have developed two new methods that could help to prevent mothers from passing on mitochondrial disease to their children (and their children’s children and so on). If approved, these techniques would take place within licenced clinics and may allow children to be born free from mitochondrial disease.
These techniques would prevent mitochondrial diseases caused by faults in mitochondrial DNA, but not those caused by faults in nuclear DNA.
Scientists are still working on these techniques to find out which will be the safest and most effective.
The below video demonstrates what mitochondria are, and how the new techniques to prevent mitochondrial disease would work:
Immediately after fertilisation, an embryo has two pro-nuclei. These are the parts of the egg and sperm that hold the nuclear DNA. Pro-nuclear transfer (PNT) involves removing pro-nuclei from an embryo with unhealthy mitochondria immediately after fertilisation.
The pro-nuclei, are then transferred into a donated embryo. This donor embryo contains healthy mitochondria, but has had its own pro-nuclei removed.
A maternal spindle is a structure within a woman’s egg that contains only the mother’s half of a child’s nuclear DNA. The father’s half of the nuclear DNA comes from the sperm.
Maternal spindle transfer (MST) involves removing the spindle from the mother’s egg before it is fertilised by the father’s sperm. The spindle is then placed into a healthy donor egg with healthy mitochondria (from which the donor’s spindle, and therefore the nuclear DNA, has been removed).