Gene Therapy and Medical Ethics · asia
Six-Year-Old Girl Dies After Base Editing: Disclosure and Oversight of a Single-Patient Gene Therapy Trial in China Questioned
The treatment, tailored for a child with a rare disease, ended in her death seven days after injection; the serious adverse event, which emerged only more than a year later, has also brought animal safety signals, family funding, and clinical oversight under scrutiny.
A gene therapy designed for just one child encapsulates both the most promising and the most difficult aspects of precision medicine. A joint investigation by several media outlets found that a six-year-old girl in China with a rare neurodevelopmental disorder died seven days after receiving an experimental base-editing treatment. Yet this outcome, which was critical to participant safety, was not promptly disclosed, and neither the relevant trial registration nor a subsequent paper reported it.
The girl had Snijders Blok–Campeau syndrome, caused by the R1025W variant in the CHD3 gene, which can cause developmental delay, speech impairment, intellectual disability, and autism-like features. The research team hoped to use an adenine base editor to directly correct the single disease-causing base. Because the complete editing toolkit could not fit into a single adeno-associated virus vector, the researchers delivered it separately using two AAV9 vectors, which were then introduced into the cerebrospinal fluid by intrathecal injection.
ClinicalTrials.gov registered the study as an early Phase 1, open-label trial with a planned enrollment of only one participant. Its primary outcome measure was drug-related serious adverse events within 26 weeks after treatment. The registration shows that the trial was conducted at Shanghai Xinhua Hospital. Its last update remains dated March 6, 2025, its status is still listed as recruiting, and no trial results have been posted.
A joint investigation by Science and Retraction Watch reported that the girl died from a severe treatment-related immune reaction seven days after the viral vectors carrying the editor were administered; her family also attributed the cause of death to a fatal immune reaction. However, the complete medical records, dosage data, and an independent determination of the cause of death have not been made public. The current description of the fatal mechanism therefore still comes primarily from investigative reporting and the family’s account, rather than a peer-reviewed clinical report.
The investigation further reported that the family contributed approximately US$860,000 to develop the personalized therapy, but neither this funding nor the girl’s death appeared in the trial record or the related Nature paper. Seven external experts interviewed also said that the animal data contained organ-toxicity signals that should not have been ignored, and that risk disclosure and independent oversight may have been inadequate. The hospital reportedly used an in-house research pathway that did not require approval from China’s national-level drug regulator, further making whether the review threshold was sufficient for high-risk gene editing a central question.
The related preclinical paper was published in February this year. It reported that base editing could improve behavioral abnormalities in mice carrying the same CHD3 variant and could broadly transduce neurons in nonhuman primates after intrathecal injection. On July 2, the paper was corrected over duplicated source values in two figures. On July 29, Nature added an editor’s note stating that the article and its data had been questioned and that an investigation was underway. These animal findings therefore can no longer be regarded on their own as sufficient assurance of safety for use in humans.
Shanghai Jiao Tong University has said it is investigating researcher Qiu Zilong. Separately, reports said that Xinhua Hospital was fined approximately RMB 24,000 by local health authorities in September 2025, but no public disciplinary action against the principal investigator was reported at the time. The questions the incident must ultimately answer extend beyond why a single treatment failed. They also include the reporting of deaths, disclosure of interests and funding, updates to trial registrations, and, when families have no alternative treatments, who is responsible for ensuring that scientific hope does not cross the boundary of acceptable risk.