A crack in the human gene editing floodgates

In the past five years, use of the gene editing technology known as CRISPR-Cas9 has exploded in research labs across the globe. The innovative technology appears to be as promising for the field of medicine as it is controversial and potentially dangerous for society.

In an attempt to rein in possible unethical misuses of gene editing, the National Academy of Sciences and the National Academy of Medicine formed a 22-member committee to study the matter and draw up guidelines. The committee advised caution in moving editing reproductive cells, also known as germline cells, but emphasized caution did not mean prohibition.

Editing germline cells means modifications will be passed down to future generations. Currently, the United States prohibits the use of federal funds to review research using heritable human germline editing. But the committee established guidelines under which germline editing could be permitted if the current restrictions expired or if countries without such restrictions wished to pursue it.

David Prentice, vice president and research director of the Charlotte Lozier Institute, said the guidelines were much too open-ended.

“It’s disappointing that the National Academies would take such a duplicitous position,” he said. “If there are ethical reasons not to allow most germline editing, those same reasons apply to any germline editing. … By leaving the door open a crack, it can be pushed open a mile.”

Marcy Darnovsky, executive director of the Center for Genetics and Society also criticized the guidelines.

“This report is a dramatic departure from the widespread global agreement that human germline modification should remain off limits,” she told The Washington Post.

CRISPR uses an enzyme called CRISPR-Cas9 which acts like a pair of scissors and cuts DNA at targeted places to remove specific genes. Researchers can then put in a new gene or just fuse the DNA strands back together. CRISPR’s precision, ease of use and relative low cost have boosted its popularity in medical research. Researchers who use gene editing on embryos for experimentation must destroy the embryos after 14 days; they are not allowed to be implanted.

CRISPR is a totally different procedure from the controversial mitochondrial replacement therapy, MRT, which uses genetic material from three people to engineer an embryo. But MRT and CRISPR both share the potential to permanently alter the human gene pool.

China has already engaged in research editing human embryos. The first clinical trial to use CRISPR to target cancer cells was approved in the United States less than a year ago, and just a little over three months ago China used the technology to inject CRISPR-edited genes into a patient for the first time.

Bioethicists warn altering the heritable human germline could have long-term, unintended consequences. Even using this method to edit somatic, or non-reproductive, cells is reason for concern. For example, using gene editing to improve muscle functioning in patients with muscular dystrophy could provide an easy segue to using it for healthy people who want more muscular bodies. Use of the technology for enhancement could create a society in which people who couldn’t afford such enhancements would be ostracized and disadvantaged.

The guidelines permit somatic cell gene editing to treat a variety of genetic disorders, but the committee ruled that, at this time, the potential risks of using the technology for enhancement outweighed the benefits. It added that with additional research, those risks would probably diminish.

According to Wesley J. Smith, senior fellow at the Discovery Institute’s Center on Human Exceptionalism, past history shows that advocates of new technological advances often appear willing to accept reasonable limitations until a controversial technology becomes doable. Then, it is suddenly “full speed ahead!” he wrote on the Discovery Institute’s Evolutionary News and Views blog: “It starts with health, and that justification is deployed to sway the public and regulators. But soon, these technologies will move to promoting enhancement and eugenic design, already seen in currently deployed reproductive technologies.”