Having a child with DNA from three people – In the news
Our DNA comes from two places, our biological mum and our biological dad. But that might change for some very special babies that could be born in the next year or so in the UK. On 3 February the UK parliament voted to allow a medical procedure using donor mitochondria. Women with mitochondrial disease worry about passing faulty mitochondria on to their children. This new method would prevent that and result in a baby with DNA from three people.
Mitochondrial diseases are rare (about 1 in 5000 people). They can affect many organ systems and cause a variety of symptoms, including seizures, muscle weakness and cramping, blindness, hearing loss and digestive problems. Mitochondria may still be present in cells but not working very well or they may be completely lost.
Some key biologicalpoints relevant to the procedure:
- mitochondria are the energy generators in cells
- most of our DNA is packaged as chromosomes in the cell’s nucleus
- mitochondria have their own separate DNA
- mitochondrial diseases can be caused by mutations in mitochondrial DNA
- mitochondria are inherited from the mother
So a woman with a mitochondrial disease caused by a mutation in mitochondrial DNA will pass the disorder on to her children. The diagram shows how the new procedure gets around this problem by using a donor egg with healthy mitochondria to carry the mother’s nucleus. This egg is then fertilised with the father’s sperm.
The ethical and safety issues have been robustly debated. Would we say that children from this new procedure will have ‘three parents’, and is that a problem? Is it alright to change any of the DNA that will be passed down that family line? View the BBC web link below to see discussion from different viewpoints.
BBC News release http://www.bbc.com/news/health-31069173 includes video of the debate in the House of Commons and people affected by mitochondrial disease.
Australian Mitochondrial Disease Foundation http://www.amdf.org.au/; view the Mito Info pages