A Chinese researcher, He Jiankui, shocked the world two weeks ago when he revealed that the world’s first genetically edited babies had been born. Jiankui claimed to have edited embryos before implanting them into the mother as part of an otherwise routine in vitro fertilization (IVF) procedure. Since his bold announcement via YouTube, the scientific community at-large – both in the United States and in China – has strongly denounced this work as deeply unethical and dangerous.
CRISPR, a relatively quick and easy gene-editing technology, is utilized in several ongoing research efforts and clinical trials to prevent or cure diseases. However, the experiment that Jiankui did is fundamentally different from any ongoing gene-editing trials. He used CRISPR to edit germline cells (which include eggs, sperm, and embryos) as opposed to somatic cells (which include other cell types in the body, such as heart, liver, or kidney cells). While genetic changes to most somatic cells remain confined to that individual, changes to germline cells have the potential to be inherited by generations to come.
Many researchers agree that CRISPR technology is too immature to even consider the ethical permissibility of making permanent inherited changes to human genomes.
Jiankui used CRISPR to disrupt the gene for CCR5, a protein on the outer surface of cells that HIV uses to enter. He claimed that disruption of CCR5 would ensure that these babies would be protected from contracting HIV infection. However, HIV can enter cells in other ways that don’t use CCR5, and there are other, safer ways of preventing and controlling HIV infection, calling into question the entire ethical premise of the research.
Jiankui’s work has reignited a much-needed dialogue about the ethics of human germline genetic editing, and it has brought to light concerns about potential unintended consequences. Scientists cannot always be certain of the effect that a genetic change might have. For example, while disrupting the CCR5 receptor might decrease the risk of HIV infection, a significant body of work suggests that this might also increase the risk of contracting other infections such as the West Nile virus. And with current gene-editing technology, there is no way to rapidly reverse genetic changes if they do not have the desired effect – or if there are other unpredictable effects, such as unintended editing at off-target sites in the genome. The general consensus in the scientific community is that CRISPR-mediated gene editing is not ready to edit the human germline. But will scientists like Jiankui continue to push forward anyway?
Managing Correspondent: Radhika Agarwal
Popular news article: https://www.nature.com/articles/d41586-018-07545-0
Image Credit: Dovidena, CC 4.0