New gene editing tool could fix most harmful DNA mutations

'Prime editing' more precise than Crispr-Cas9, but still needs time before use on humans

Scientists have raised fresh hopes for treating people with genetic disorders by inventing a powerful new molecular tool that, in principle, can correct the vast majority of mutations that cause human genetic diseases.

The procedure, named "prime editing", can mend about 89% of the 75,000 or so harmful mutations known to mangle the human genome and lead to conditions such as cystic fibrosis, sickle cell anaemia, and a nerve-destroying illness called Tay-Sachs disease.