On Sept. 14, 1990, a four-year old girl, Ashanti DeSilva, became the first gene therapy patient. She had adenosine deaminase (ADA) deficiency, a genetic disease which left her defenseless against infections.

Doctors at the National Institutes of Health (NIH) Clinical Center took white blood cells from her, and the normal genes for making adenosine deaminase were inserted into them. The corrected cells were reinjected into her. Dr. W. French Anderson helped develop this landmark clinical trial when he worked at the National Heart, Lung, and Blood Institute.