Jesse, who suffered from a chronic liver condition, died in September, four days after being injected with a virus designed to carry the gene into his body. Researchers hoped that this would cure him permanently. Instead, he developed a high temperature, breathing difficulties and other complications that proved fatal.
Jesse was a volunteer in the programme, which was based at one of the most respected medical research centres in the US, at the University of Pennsylvania in Philadelphia. Taking part in experimental programmes at teaching hospitals is one way that people who are chronically ill, and so uninsurable in the US system of private health-care, can obtain state of the art treatment.
At the time, Jesse Gelsinger's death was not directly attributed to the gene treatment. It was only late last month that a report established that it probably killed him. It transpired that as many as three people may have died as a result of experimental gene therapy in the US, but Jesse Gelsinger's is the first case to be documented.
Gene therapy, which is still at a very early experimental stage, holds out the prospect of curing genetically transmitted diseases if the faulty gene can be corrected or replaced. Experiments on rats had produced hopeful results, and the University of Pennsylvania obtained funding for human treatment.
With the stakes so high, this week's conference at the National Institutes of Health uncovered depths of passion that were exceptional in the normally cool and collected world of medical science.
Several of the researchers, including the head of the programme, James Wilson, apologised for breaches of the regulations, while parents of sick children begged for the experiments to be allowed to continue. However, participants also heard revelations about the University of Pennsylvania programme that cast serious doubt both on its effectivenessand reliability.
Officials from the US Food and Drug Administration, which oversees the introduction of new drug treatments, said that they had not been told of deaths among monkeys more than a year before Jesse Gelsinger died. The university researchers for their part admitted that they had accepted Jesse even though he did not strictly qualify under FDA regulations.
The FDA is expected to respond by announcing a new study to consider how the regulations can be tightened to reduce the risks to patient.