Mei's fatal gene-editing trial: $860k therapy for CHD3 mutation ends in death

Overview

A six‑year‑old girl named Mei died of thrombotic microangiopathy seven days after receiving an experimental base‑editing gene therapy targeting her CHD3 mutation at Xinhua Hospital in Shanghai. The therapy cost her parents more than $860,000 and was never made public until investigated by Science and Retraction Watch.

Background

Mei was diagnosed with global developmental delay linked to a single‑base T→C mutation in the CHD3 gene, causing Snijders Blok‑Campeau syndrome. Her parents sought treatment after learning of neuroscientist Zilong Qiu’s work on base editors for neurodevelopmental disorders.

Trial Design and Funding

The parents funded the majority of the preclinical work, wiring money to Qiu’s former student for base‑editor design, to a Chinese affiliate of a U.S. firm for virus production, and to PriMed for monkey studies. They also paid researcher Kan Yang $130,000 directly for analysis work and gave Qiu gifts such as iPhones and Maotai liquor. The informed consent form stated that participation would incur no additional costs, but the hospital doctor acknowledged that the family’s payments gave them a stake in the project.

Safety Concerns Ignored

Before Mei’s infusion, a primate toxicology study at PriMed reported moderate to severe liver damage in all four monkeys given the therapy, with one high‑dose monkey showing kidney damage consistent with thrombotic microangiopathy. The hospital ethics committee approved the trial without reviewing this final safety report. Experts including Steven Gray and James Wilson said the liver/kidney data should have triggered additional dose‑finding studies.

Procedure and Immediate Aftermath

On 23 March 2025, doctors infused trillions of AAV9 viruses carrying the base editor into Mei’s spinal fluid. She developed fever, low platelets, and ceased urination, signs of kidney injury. Seven days later she died of thrombotic microangiopathy, a reaction noted as a possible outcome in the consent form but not described as potentially fatal.

Official Response and Lack of Accountability

Two days after Mei’s death, the hospital’s ethics board concluded the treatment was “definitely related” to her death. The local health department fined the hospital approximately $3,600 for failing to oversee the trial and for not registering it as commercially sponsored research. No public sanction was imposed on Zilong Qiu or the overseeing physician Yongguo Yu.

Publication Omission and Expert Critique

The Nature paper that later described the base‑editing therapy omitted any acknowledgment of Mei’s participation, removed a sentence thanking the family for support, and excluded the primate safety data showing liver and kidney injury. After peer review, control samples were added but processed at different times and microscope settings, complicating comparison. Experts such as David Sanders and Mike Rossner questioned the image integrity, while Steven Gray expressed skepticism about the edited neuron quantification.

“It’s completely unconvincing,” says David Sanders, a biochemist at Purdue University who has studied gene therapy. “One can’t have the confidence that one isn’t mostly looking at background staining.”

“To not acknowledge one of the sources of funding should be enough for retraction,” Sanders says.

Parents’ Reaction and Ongoing Impact

Mei’s parents, using the pseudonyms Jason and Linda, complained to Qiu’s university demanding an investigation and retraction of the Nature paper. The university’s dean’s office replied that it would take no action against Qiu, characterizing the payments to Yang as “research service fees” and stating the Nature paper “bears no relation to the experiments you funded.” The family has since moved homes, limited social contact, and continues to grieve.

“Learning the reality of these missing safeguards has fundamentally changed how we now view the entire project,” says Jason, Mei’s father.

Lessons and Calls for Transparency

Commentators on Hacker News highlighted the need for families to advocate for themselves, the danger of downplaying risks in novel brain‑targeted gene therapies, and the importance of publishing negative outcomes.

“You must advocate for yourself and your loved ones in the medical system, because doctors will not do it for you,” notes @senderista.

“Ethics and safety concerns seemed to get ignored all the way to the actual treatment,” observes @lconnell962.

“The worst to me seems to be that the researchers/doctors seem to have downplayed the risks,” says @fabian2k.

“There’s something deeply unjust about that… a kind of ‘adding insult to fatality,’” remarks @Terr_ regarding the enthusiastic reception of the Nature paper unaware of Mei’s death.

“Cases like this are heartbreaking, but they’re also a reminder that failures like this need to be published just as prominently as success,” states @1saadcodes.

These perspectives underscore calls for full data disclosure, rigorous safety review, and transparent reporting of both successes and failures in gene‑editing research.