Researchers have developed a gene-editing treatment for prion disease that extends lifespan by about 50 percent in a mouse model of the fatal neurodegenerative condition. The treatment, which uses base editing to make a single-letter change in DNA, reduced levels of the disease-causing prion protein in the brain by as much as 60 percent. The work demonstrates that lowering levels of the prion protein improves lifespan in animals that have been infected with a human version of the protein.