A new twist has emerged in the gene-editing controversy created by Chinese scientist He Jiankui. South China Morning Post has posted a video of He, made during a conference in Hong Kong, in which he says that a second woman may be pregnant with an embryo that he genetically modified using CRISPR-Cas9.
The revelation is the latest development in a saga that has caused an uproar in the scientific community worldwide and led to statements from the American Society for Reproductive Medicine (ASRM)and the American Society of Human Genetics (ASHG), among others, denouncing He’s work.
He’s first announcement, made on November 26 and reported by Nature, was the revelation that twin girls had been born earlier in the month following his alteration of their genes to disable the CCR5gene, which plays a key role in HIV infection of cells. Editing of the embryos was done with CRISPR-Cas9, a system that can be programmed to target specific stretches of genetic code and to edit DNA at precise locations.
He, a scientist at Southern University of Science and Technology in Shenzhen, China, claimed that the twins are healthy and that he only edited the target gene. But his work has not been verified or published.
The university is investigating He’s claims and in a statement published online, said the work “has seriously violated academic ethics and codes of conduct” and called the event “deeply shocking.” According to a November 29 report by NBCNews, the Chinese government has ordered a temporary halt to research on humans involving the editing of human genes. The rationale given by He for his editing—paternal HIV positivity—has been called into question because of negligible risk of fetal of HIV transmission from father to child.
In its statement on the report about He’s work, ASRM said that gene editing “should only be used clinically after careful study done with vigorous oversight.” The organization encouraged leaders around the world to “implement a sound regulatory system that allows for responsible investigation and innovation to improve human health.”
ASHG said that the report by He “would be at odds with field consensus that germline editing is not ready for human use.” The organization reaffirmed the “cautious yet proactive approach” to the technology that was reflected in its 2017 position statement, which asserted the following positions:
- At this time, given the nature and number of unanswered scientific, ethical, and policy questions, it is inappropriate to perform germline gene editing that culminates in human pregnancy.
- Currently, there is no reason to prohibit in vitro germline genome editing on human embryos and gametes, with appropriate oversight and consent from donors, to facilitate research on the possible future clinical applications of gene editing. There should be no prohibition on making public funds available to support this research.
- Future clinical application of human germline genome editing should not proceed unless, at a minimum, there is (a) a compelling medical rationale, (b) an evidence base that supports its clinical use, (c) an ethical justification, and (d) a transparent public process to solicit and incorporate stakeholder input.