An investigation by Science and Retraction Watch has uncovered details about a clinical trial that resulted in the death of its sole patient: a 6-year-old girl with a rare genetic mutation affecting her cognitive development. Her death has never been reported publicly, even though the medical team published its preclinical work in Nature earlier this year. Also omitted from the paper and trial records: The family paid more than $800,000 to fund the therapy’s development. The family has asked the authors to withdraw the paper, and experts we spoke to raised issues they say may warrant a retraction. The beginning of the story, by Retraction Watch contributing writer Brendan Borrell, is below, lightly edited for brevity. Read the full story at Science.
The 6-year-old girl tugged on her mother’s hand as they pressed through the doors of the hospital in Shanghai. Behind them, her father rolled a large suitcase with everything the child needed for the weeklong stay. She told her parents it felt like they were going on vacation. In fact, they brought her here for an experimental gene therapy.
The girl was slipping behind her peers in kindergarten. She still spoke in simple sentences and ate with training chopsticks. Underneath it all was a single mutated DNA base, a T that should have been a C.
“Your ‘book’ has a small mistake, which has caused you to have a disease that affects your growth,” read the children’s version of the informed consent form from the hospital. “Over time, it can get more serious.”
Doctors hoped to repair that mistake while her brain was still building itself. It would be a clinical trial of one, funded in part by $860,000 the parents had scraped together from their own savings and from relatives.
The parents felt they were in good hands. Xinhua Hospital, which is affiliated with the Shanghai Jiao Tong University School of Medicine, was acclaimed for its pediatrics department. It was the first Chinese institution to perform open heart surgery on infants, and the first in the country to separate conjoined twins. If all went well, the girl would be the first person in the world to receive a gene-editing therapy directed at the brain. It would rewrite the mutated gene in her neurons, restoring the needed DNA base so she could make a vital protein.
Leading the effort was Zilong Qiu, a neuroscientist at the university’s brain center, the Songjiang Research Institute. At the time, in late March 2025, Qiu was one of several researchers around the world vying to push base editors — a more precise form of the powerful gene editor CRISPR — into custom treatments for children with rare diseases. One month earlier, KJ Muldoon, an infant with a life-threatening metabolic disorder, had quietly received his first intravenous infusion of one such treatment at the Children’s Hospital of Philadelphia.
Although news that base editing saved “Baby KJ” would soon rocket around the world — Science named the feat one of the runners-up for its 2025 Breakthrough of the Year — the story of what happened at Xinhua Hospital has remained hidden. An entry for the study posted to ClinicalTrials.gov has not been updated for more than a year. And when Qiu and his colleagues published proof-of-concept animal studies related to the trial in Nature early this year, they stripped the paper of references to the family and its financial contributions, noting only that “bridging the gap between preclinical research and clinical translation remains a significant challenge.”
That vague language glossed over tragedy: Seven days after the girl’s medical team infused trillions of viruses carrying the recipe for the base editor into her spinal fluid, she died of a severe immune reaction linked to the therapy, Science and Retraction Watch can now reveal.
According to official documents and accounts provided by the girl’s parents, the hospital had allowed Qiu’s experimental treatment to proceed under a regulatory provision that does not require approval from national regulators. The lax oversight of this recent trial and the failure to publicly report the fatality “shows the gap between what is intended and what has been put in place,” says Joy Zhang, a sociologist at the University of Kent who has written about the pervasive culture of secrecy in Chinese scientific institutions.
Seven experts in fields including genetics, virology, and bioethics who reviewed details of the Nature study and the clinical trial for Science and Retraction Watch expressed concern that Qiu and his team downplayed the trial’s risks in describing them to the parents, overlooked safety signals in animal studies, and proceeded even though success was unlikely. “This shouldn’t have gone to trial,” says Steven Gray of the University of Texas Southwestern Medical Center, who develops viruses for gene therapy.
Gray and several of the other experts are calling for a full review of the images and other data in submitted and published versions of the Nature paper and full disclosure of the study’s funding. Some of the issues might warrant a retraction, they say. Neither Qiu nor his university or the hospital responded to multiple requests for comment for this story, and Nature says it was not aware of the issues surrounding the clinical trial before it published the group’s paper.
The girl’s parents have decided to tell her story now because they are angry about what they feel is a lack of accountability by the researchers and the institutions. “Learning the reality of these missing safeguards has fundamentally changed how we now view the entire project,” says the father, a software engineer. “We did not realize how unusual and dangerous many of the arrangements were.”
Read the full story in Science.
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