In this Monday, Nov. 13, 2017 photo, Brian Madeux, starts to receive the first human gene editing therapy for Hunter syndrome, as his girlfriend Marcie Humphrey, left, applauds at the UCSF Benioff Children's Hospital in Oakland, Calif. At right is nurse practitioner Jacqueline Madden. Gene editing aims to permanently change someone's DNA to try to cure a disease. (AP Photo/Eric Risberg)