Scientists make potential breakthrough in preventing set of inherited diseases

A new technique aimed at preventing a set of rare inherited diseases has been declared safe by leading scientists.

Mitochondrial diseases affect around one in 5,000 people. They can be debilitating and sometimes fatal. They are caused by faulty mitochondria - these are the power stations within each of our cells and we get them all from our mothers. Because mitochondria appear in every cell, any faults could manifest themselves as problems in everything from the brain to the eyes, heart, muscle or almost anything else.

Preventing these diseases has traditionally been beyond medical treatment. But now scientists at the Wellcome Trust Centre for Mitochondrial Disease at Newcastle University have perfected a technique that could prevent faulty mitochondria being passed down the generations. The published their results today in the journal Nature.

Their technique is called called “early pronuclear transfer”. It involves taking the nuclear DNA from an egg that has been fertilised but has faulty mitochondria, and then inserting that DNA into a donor egg that has healthy mitochondria, but which has first had its own nuclear DNA removed.

The team in Newcastle studied their procedure on more than 500 donor eggs from 64 women. They showed that early pronuclear transfer not only reduced the amount of faulty mitochondrial DNA passed on to an embryo, but also that the embryo wasn’t harmed in the process. They said they were confident that, if implanted, these embryos would create normal, healthy pregnancies.

Professor Mary Herbert, one of the leaders of the study, said: “Having overcome significant technical and biological challenges, we are optimistic that the technique we have developed will offer affected women the possibility of reducing the risk of transmitting mitochondrial DNA disease to their children.”

Professor Doug Turnbull, director of the Centre for Mitochondrial Research, and a co-author of the paper said using normal human eggs was a major advance towards preventing transmission of mitochondrial DNA disease.

The scientific hurdles for this potentially lifesaving procedure have now been cleared. It's now up to the government regulators - the Human Fertilisation and Embryology Authority - to decide when it will become available in the clinic. Prof Turnbull said that, if the decisions go well, the procedure might be available to women by the end of this year.