Epigenetic editors are a gentler form of gene editing

More than a decade ago Sonia Vallabh, a lawyer, and her husband, an engineer, decided to retrain as molecular biologists. They had an urgent motivation. Dr Vallabh’s mother had died suddenly of a mysterious dementia. An autopsy had revealed the cause to be prion disease, in which the prion protein, the normal function of which is unclear, changes form and spontaneously clumps together and causes the brain to die. Most prion disease is infectious, set off by exposure to an already clumping protein. In this case, it was genetic. “I learned that I’d inherited her mutation,” Dr Vallabh says. They needed to find a cure before the disease came for her, too.