Mitochondria are responsible for producing about 90% of the body’s energy and a wide range of cellular processes, so it's no surprise that defects can have incredibly devastating consequences. There is no cure for mitochondrial disease, which affects about 1 in 6000 people. Defects in mitochondrial DNA are passed down exclusively by the mother.
In order to stop those defective genes from being passed down, a new technique utilizes the nuclear DNA of the mother along with the mitochondrial DNA of a donor, to create one healthy egg. Effectively, the resulting baby would have three biological parents. Assuming there are no huge legal obstacles, this technique could be ready for human use within two years, according to the report from a panel of scientists from the Human Fertilisation and Embryology Authority (HFEA) in the UK. This is the third review session of this technique by the HFEA.
There are two different techniques used for creating three parent IVF:
Embryo repair: The first technique involves fertilizing two eggs—one from the mother, one from the female donor—with the father’s sperm, via in vitro fertilization. The pronuclei, which contains nuclear DNA of the male and female, are removed from both embryos. The pronuclei extracted from the donor egg is destroyed, and the one from the intended mother and father are inserted into the donor’s embryo
[Image credit: HFEA via BBC]
Egg repair: The second technique requires an unfertilized egg cell from the mother and the donor, and the nuclei are removed. The donor’s nucleus is destroyed, and the mother’s nucleus is inserted into the donor’s egg. The complete egg cell is then ready to be fertilized by the father via IVF.
[Image credit: HFEA via BBC]
The HFEA panel concluded that there’s really no way to assess the safety of this IVF technique in humans until it has been done, and it will likely take about two years to do all of the necessary experimentation before concluding one way or another. They also don’t feel the technique is necessarily unsafe either, but it needs to be explored properly. However, this technique was used in Macaques back in 2009. The four offspring, all males, are still alive and healthy, with normal mitochondrial function.
Aside from the obvious concerns of safety, there are ethical concerns to be addressed as well. Some believe that if this type of IVF is permitted, it will open the door to further genetic modification and discrimination in humans, until we’re living in a GATTACA-style world or promoting eugenics. It is important to remember that this isn’t about designing babies to be smart, athletic, and have great cheekbones. This has the potential to rid very specific family lines of a horrible disease while still maintaining all of the good maternal genes to be passed down.
Following the release of this report, officials in the Department of Health will read and decide in the coming months whether or not to repeal current prohibitive regulations, allowing experimentation to begin. Government officials have spoken highly of the potential of the technique, provided it can be done safely.
On the other side of the pond, the US’s Food and Drug Administration (FDA) has been deliberating this technique as well. In February, they conducted a public meeting to collect facts from experts and concerns from the public. Their decision has not yet been made, though many believe they will be favorable of the idea.
[Hat tip: James Gallagher, BBC]