The preliminary report on the death of Jesse Gelsinger of Tucson, Ariz., strongly suggests that an infusion of corrective genes, encased in a weakened cold virus, led to the unusual immune system failure that caused multiple organ failure, says James M. Wilson, director of the University of Pennsylvania Institute for Human Gene Therapy. He suffered from ornithine transcarbamylase deficiency, or OTC, a genetic disorder that leaves the body unable to produce enzymes that remove ammonia from the body.
Ammonia is a byproduct of protein processing.
Researchers say they still do not understand specifically why Gelsinger, who was relatively healthy except for the gene disorder, died. The case is likely to revive a debate about using patients in gene-therapy trials who are not close to death. The trial involving Gelsinger was the first gene-therapy trial in the country not to involve seriously ill people. Gelsinger's father, Paul, says his son knew there was a chance he could die from participating in the study, but he accepted the odds because he wanted to help himself and others. Seventeen other patients had been through the procedure without ill effects, and Paul Gelsinger says he encouraged his son to participate.