Months after he became the first infant to undergo gene-editing therapy to treat his rare genetic disorder, 1-year-old KJ Muldoon is accomplishing another first — his first steps. The Children's Hospital of Philadelphia (CHOP) shared a Dec. 17 news release that KJ is walking and getting ready to spend Christmas at home with his parents and three siblings after spending his first holiday season in a hospital room in 2024. "It's all been a miracle. It's the only way to describe it," his dad, Kyle Muldoon, told Good Morning America on Dec. 18...