The gene editing tech that uses 'molecular scissors'
In 2012 a form of gene editing was discovered with great fanfare, it is called CRISPR Cas9. Put simply, it uses "molecular scissors" to alter a very specific strand of DNA - either cutting it out, replacing it or tweaking it.
The BBC met one of the companies working to get the science from the lab to the clinic.
Producer: Adrienne Murray; Camera: Ian Cartwright; Picture editor: Sara Hegarty