The first gene therapy patient was a 4-year-old girl in 1990
In 1990, four-year-old Ashanti DeSilva became the first person to receive gene therapy, after NIH doctors inserted a working copy of the ADA gene into her white blood cells to treat her severe combined immunodeficiency. The fix targeted existing cells rather than her stem cells, so it wasn't permanent, but it proved genes could be safely inserted into a living person.