CRISPR-Cas9 genome editing exploits the CRISPR-Cas system to modify a genome in a targeted manner. Guided by RNA, the Cas9 endonuclease breaks DNA at a target sequence. Imprecise repair of the ...

Doctors harvest stem cells from the patient’s bone marrow and then send them off to a lab, where CRISPR is used to turn up the production of another, functional version of haemoglobin.