CRISPR Injected into the Blood Treats a Genetic Disease for First Time

A new CRISPR-based treatment for a rare, deadly liver disease depends on an injection containing both a messenger RNA encoding a DNA-cutting enzyme (white) and another RNA (blue) that guides it to a specific gene sequence (green). The gene editor CRISPR excels at Exing disease mutations in lab-grown cells. But using CRISPR to treat most people with genetic disorders requires clearing an enormous hurdle: getting the molecular scissors into the body and having it slice DNA in the tissues where it’s needed. Now, in a medical Erst, researchers have injected a CRISPR drug into the blood of people born with a disease that causes fatal nerve and heart disease and shown that in three of them it nearly shut off production of toxic protein by their livers.