The creepily named Human Fertilisation and Embryology Authority in the United Kingdom is thinking about approving an in vitro fertilization (IVF) technique aimed at curing mitochondrial diseases. Mitochondria are tiny powerplants with their own small geneomes that float by the hundreds in the cytoplasm of cells. One in 2,500 children are born with diseases associated with broken mitochondria.
To prevent children from being born with these diseases, fertility specialists are proposing to implement two procedures: (1) maternal spindle transfer and (2) pro-nuclear transfer. In maternal spindle transfer genes are taken from nucleus the egg of the prospective mother whose mitochondria are defective and installed into a donor egg with healthy mitochondria from which nuclear genes have been removed. The reconstituted egg is then fertilized. In pro-nuclear transfer involves taking nuclear material from a fertilized egg before the nuclei of the sperm and egg have fused and installing it into a donated enucleated egg.
Treating mitochondrial diseases in embryos actually began in the United States in 2001 when researchers at a fertility clinic in New Jersey transfered cytoplasm containing healthy mitochondria from donor eggs into the eggs of women whose mitochondria were defective. Before the regulators at the Food and Drug Administration (FDA) outlawed it, nearly 20 children were born as a result of the procedure. In this case, healthy donor mitochondria were mixed with defective maternal mitochondria.
The Independent reports that researchers are now checking 17 of the now-teenaged children to see how they are faring. That's fine, but Independent is suggesting that if researchers find something wrong that would impact the decision to go forward with the similar technique in Britain. It shouldn't. From The Independnent:
The findings of the follow-up will be keenly scrutinised by Britain's fertility watchdog, the Human Fertilisation and Embryology Authority (HFEA), which is charged with making sure that a similar technique called mitochondrial donation is safe.
"We do not know of any follow-up of children born as a result of cytoplasmic transfer but we would certainly want to know the results of such a follow-up," said an HFEA spokesman.
As noted, the earlier cytoplasm transfer technique involved mixing healthy and defective mitochondria; the new procedures do not. Nevetheless, the results of the follow up study will surely be of interest to people who want to avail themselves of these techiques, but the decision to use these IVF techniques to prevent mitochondrial diseases should be made by the would-be parents. After all, they are the people who will reap the rewards and bear the burdens of being parents.