Page URL:

Genome editing prevents mitochondrial disease in mice

27 April 2015
Appeared in BioNews 799

A gene-editing technique that may prevent mutated mitochondrial DNA (mtDNA) from being passed down from mother to child has shown success in an animal study.

Developed by researchers at the Salk Institute for Biological Studies, in La Jolla, California, the technique works by using DNA-cutting enzymes to delete mutated mtDNA, leaving healthy mitochondria intact. By reducing the amount of faulty mtDNA, the technique aims to restore the balance in favour of healthy mitochondria, reducing the amount of faulty mtDNA passed down to offspring to the point where it does not result in disease.

'This technique is based on a single injection of mRNA into a mother's oocytes or early embryos and therefore could be easily implemented in IVF clinics throughout the world', said Professor Juan Carlos Izpisua Belmonte senior author of the study.

He added: 'This technology is not perfect, it cannot eliminate all the bad DNA, but by eliminating some, it'll be enough to prevent the transmission of these diseases to the kids of affected mothers.'

The researchers first demonstrated the technique by targeting one of two types of mtDNA carried in mouse eggs, which resulted in the birth of healthy mice with low levels of the targeted mtDNA and which also displayed normal mitochondrial function. These mice subsequently gave birth to mice with 'barely detectable' levels of the targeted mitochondria.

The researchers then applied the technique to target human mtDNA mutations inserted into mouse eggs known to cause two mitochondria-related diseases. The application of the technique resulted in a 'significant reduction' in mutated mtDNA.

'We expect that this method will reduce the percentage of mutated mitochondrial DNA below the threshold for triggering mitochondrial diseases in humans', Professor Belmonte said.

There are currently no cures or effective treatments for mitochondrial disease, which can lead to serious health problems. The researchers say the technique is 'safer, simpler, and more ethical' than mitochondrial donation (see BioNews 789, 790 and 790), as the gene-editing technique avoids the need to use DNA from three people. Professor Belmonte also says that the technique could be safer than nuclear genome editing.

The team now plans to test the safety and efficacy of this technique in surplus eggs donated by fertility patients with mitochondrial diseases.

14 August 2017 - by Shaoni Bhattacharya 
A new approach to genetic analysis may lead to a faster way to diagnose mitochondrial disease...
25 April 2016 - by Dr Julia Hill 
A study has found that stem cells from older people accumulate high numbers of mitochondrial DNA mutations, which could limit their therapeutic value...
1 February 2016 - by Ryan Ross 
UK fertility doctors are seeking permission to trial a new IVF treatment that involves transferring additional mitochondria into egg cells before fertilisation...
20 July 2015 - by Dr Julia Hill 
Scientists in the USA have demonstrated how stem cell techniques may benefit people with incurable mitochondrial diseases. The research suggests it might be possible one day to replace diseased tissue in patients affected by the disorders...
2 March 2015 - by Sandy Starr 
The House of Lords has voted by 280 to 48 to pass regulations permitting mitochondrial donation. This makes the UK the first country in the world to legislate for the use of mitochondrial donation techniques in treatment...
23 February 2015 - by Sarah Norcross 
Earlier this month, a large majority of MPs voted in favour of Regulations that permit mitochondrial donation to be used in treatment. But mitochondrial donation will not become lawful in the UK unless the House of Lords also supports the Regulations, and the deciding vote is due to take place on 24 February...
16 February 2015 - by Philippa Taylor 
In a recent Progress Educational Trust debate, 'Mitochondrial Donation: Is It Safe? Is It Ethical?', I spoke about the ethical issues raised by techniques to avoid the passing on of inherited mitochondrial disorders...
9 February 2015 - by Dr Rachel Montgomery 
Held at the Houses of Parliament, and organised by the Progress Educational Trust (the charity that publishes BioNews), this public debate was well attended. With all the chairs taken and many more people standing, people clearly felt it was important to discuss these issues...
4 February 2015 - by Sandy Starr 
The House of Commons voted by 382 to 128 to pass regulations permitting mitochondrial donation, a majority of 254...
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.