Summary
The gene editor CRISPR excels at fixing 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 first, 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 a toxic protein by their livers. Although it’s too soon to know whether the CRISPR treatment will ease the symptoms of the disease, known as transthyretin amyloidosis, the preliminary data reported last week are generating excitement about what could be a one-time, lifelong treatment. The work also marks a milestone in the race to develop treatments based on messenger RNA, the protein-building instructions naturally made by cells.