Will gene-editing of human embryos ever be justifiable?

Will gene-editing of human embryos ever be justifiable?

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By Sally Robertson, B.Sc.Apr 30 2019Reviewed by Kate Anderton, B.Sc. (Editor)

World-leading medical ethicist Professor Arthur Caplan has published a series of recommendations with the aim of addressing worldwide concerns over gene editing of human embryos.

The article, which was recently published in the journal PLoS Biology, was fuelled by the acts of He Jiankui, who announced last year that he had created the world’s first genetically edited babies. The fact that the babies had been created without ethical debate or the benefit of scientific review caused vociferous condemnation and worldwide disdain.

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Unacceptable and unlawful

In the current article, Caplan recounts the announcement Jiankui made at a press conference held at the Human Genome Editing Summit in Hong Kong on November 25th, 2018.

Jiankui announced that he had produced a set of twins who had been genetically modified to be resistant to HIV infection. He achieved this by deleting CCR5 - the gene that encodes the cell membrane receptor that HIV uses to enter immune cells. Jiankui claimed to be proud of the results, calling the babies “normal and healthy” and revealing that another couple involved in the project were currently pregnant with a gene-edited embryo.

Scientists and ethicists worldwide condemned the work, calling it a violation of the laws of ethics. The scientific community rebuked Jiankui for unduly experimenting with human embryos and for using potentially unsafe technology on human embryos.

More than 100 scientists declared the work as “outside the boundaries of acceptable science” and the Chinese government halted Jiankui’s gene editing work almost immediately calling it unlawful, unethical and unacceptable.

Unpredictable effects

A study by UCLA researchers published earlier this year fuelled further concerns over the controversial experiment. The scientists provided evidence that the CCR5 receptor suppresses memories and synaptic connections. This means that as well as being resistant to HIV, the baby girls may have enhanced cognition and memory.

Writing in the journal Cell, Alcino Silva and colleagues said that people who lack at least one copy of CCR5 tend to go further in education, implying that the protein plays a role in intelligence.

However, Silva said there is a big difference between trying to correct deficits in cases of poor health and trying to create human enhancement.

“The simplest interpretation is that those mutations will probably have an impact on cognitive function in the twins,” said Silva. He added that the exact effect on the girls’ cognition cannot be predicted, which is why such experiments “should not be done.”

Now, Caplan, founding director of the Division of Medical Ethics at NYU School of Medicine, refers to a major flaw in medical research that has been brought to light by the controversial work.

“A deep understanding of the mechanisms and potential side-effects of embryo editing is an absolute pre-requisite to any further discussion of its implementation,” he says. “At present, human embryonic editing, particularly in regard to how DNA is repaired, following an induced break, is poorly understood.”

Moratoriums are not enough

Caplan’s article raises the question of what now needs to be done to ensure germline gene editing meets acceptable standards.

"The announcement of He Jiankui’s germline editing of human embryos has been followed by a torrent of almost universal criticism of the claim on scientific and ethical grounds. That criticism is warranted,” says Caplan.

He adds that there is little room for anything other than vociferous condemnation of Jiankui’s announcement and that presenting the results of ground-breaking work by press conference and YouTube “is not science.”

Caplan states that the question now is not whether the experiment conducted in China was done in an ethical manner, given that it clearly was not, but how conducting germline editing in humans can be justified moving forwards.

If such work is justifiable, a serious, rigorous framework must be imposed that ensures that such research is done following the highest ethical standards that both protect human subjects and ensure public trust and support.”

Many researchers had been calling for moratoriums, but these were already in place when Jiankui conducted his work.

An ethical framework for research

In his article, Caplan provides a series of recommendations, including:

• A thorough investigation of any conflicts of interest by organizations managing the studies,
• Enhanced informed consent from participants,
• The banning of  “exclusive” rights to research results for media outlets,
• The prohibition of the publication of any improperly reviewed research that involves embryos,
• Involvement of properly qualified and trained ethics committees and internal review boards,
• The development of a public database where any related research can be documented.

If such work is justifiable, a serious, rigorous framework must be imposed that ensures that such research is done following the highest ethical standards that both protect human subjects and ensure public trust and support."

Source:

Caplan A (2019) Getting serious about the challenge of regulating germline gene therapy. PLoS Biology. 17(4): e3000223. doi.org/10.1371/journal.pbio.3000223.