Child dies after experimental genome editing in China

A six-year-old girl has died following an experimental genome editing treatment, prompting an investigation into the clinical trial by the university involved.

The child received the experimental treatment in March 2025 as part of a single-participant trial at Xinhua Hospital, affiliated with Shanghai Jiao Tong University School of Medicine in China. The therapy was designed to correct a genetic mutation affecting brain development and involved somatic genome editing using base editing, achieved via an infusion into the fluid surrounding the spinal cord. According to a joint investigation by Science magazine and Retraction Watch, the girl had developmental delay and learning difficulties. She experienced a severe immune reaction and died within a week of receiving the treatment. The death was not publicly disclosed at the time.

'The death of the child subject to gene therapy through the use of an experimental base editing intervention is very sad. It is hard to know if it was avoidable, but it seems it was not carried out following best practice,' Professor Robin Lovell-Badge – chair of trustees at PET (the Progress Educational Trust), and group leader at the Francis Crick Institute in London – told BioNews. 'The hospital authorities had allowed it to proceed under a regulatory provision that did not require approval from national regulators, essentially as a last resort, but perhaps they were also too keen to be first to use the methods to treat a brain disease. Instead, they may have set the field back.'

The trial was led by neuroscientist Dr Zilong Qiu, and is the first known use of a genome editing therapy designed to target the brain in a human participant.

According to the Science/Retraction Watch investigation, the girl's parents contributed more than US$800,000 toward developing the therapy, including related animal studies. The investigation also raised concerns about whether the parents had been given sufficient information to provide fully informed consent.

'Learning the reality of these missing safeguards has fundamentally changed how we now view the entire project,' the child's father told Science. 'We did not realise how unusual and dangerous many of the arrangements were.'

The experimental treatment relied on adeno-associated viruses (AAVs) to deliver the base-editing components into the brain, with the aim of correcting the faulty gene in a sufficient number of neurons to successfully treat the child's condition. Although AAV vectors are widely used in gene therapy, the very high doses required for this type of approach can trigger immune and inflammatory responses.

'While it is possible that there was an error in the design of the guide RNAs or their manufacture, it seems to me to be far more likely that it was the virus overload that killed the child, not the base editing,' Professor Lovell-Badge told BioNews.

The researchers went on to publish a paper in Nature describing the treatment in animal models. According to the Science/Retraction Watch investigation, the paper did not disclose findings from the final preclinical toxicology study, in which all four macaques given the treatment developed moderate-to-severe liver damage and one high-dose animal also developed kidney damage. The paper also omitted to mention that the therapy had already been administered to a child with the condition, and that the child had died within a week of treatment. Nature has since added an editor's note to the paper, cautioning readers that 'concerns have been raised regarding this article' and that 'action will be taken if appropriate as soon as the investigation into the concerns is complete'.

The university involved in the experimental treatment has now launched its own separate investigation into the circumstances surrounding the clinical trial.

'I don't think these kinds of experiments should stop, but we need to make sure we are appropriately careful about them,' Hank Greely, professor of law at Stanford University, told Science. 'It's so easy to be blinded by hope – whether it's hope for your kid, hope for your research, or hope for your company.'

The case has renewed scrutiny of China's oversight of experimental genome editing research. It follows the 2018 case of He Jiankui, who was imprisoned after creating the world's first known germline genome-edited babies, prompting international criticism and highlighting gaps in the regulation of emerging technologies (see BioNews 977, 991 and 1029).

A new statutory framework governing biomedical technologies, clarifying requirements for cell and gene therapies (including approaches that involve genome editing), has recently come into force in China. With regard to oversight, ethics review and informed consent, the new framework may help China to meet the World Health Organisation's 2021 recommendations for governance of genome editing (see BioNews 1103).

'With respect to the regulatory issues, there is hope that new rules – governing the way that clinical interventions are managed in China – will prevent similar stories happening in the future,' Professor Lovell-Badge told BioNews.