First gene-editing in human body attempt Gene-editing has been attempted on cells inside a patient, in a world first by doctors in California.
Brian Madeux, 44 from Arizona, was given the experimental treatment to try to correct a defect in his DNA that causes Hunter's syndrome.
Mr Madeux says he was prepared to take part in the trial as he is "in pain every second of the day".
It is too soon to know whether or not the gene-editing has worked in Mr Madeux's case. BBC News