Scientific committee draws line at using gene editing to create designer babies

By Sheryl Ubelacker, The Canadian Press

TORONTO – Genome editing, a powerful technology that allows researchers to add, remove or replace snippets of DNA from cells, should only be used for the potential treatment or prevention of serious diseases and disabilities — not to produce “designer babies” with traits that could be passed on to future generations, an international committee of scientists says.

In a report released Tuesday, the U.S. National Academies of Sciences and Medicine outlined recommendations for global researchers as they go forward with clinical trials using genome-editing technology, which has raised ethical concerns among both scientists and the public.

While the practice of gene editing is not new, a highly precise tool known as CRISPR/CAS 9 has revolutionized scientists’ ability to alter DNA. It led to an explosion of research and would-be applications for a wide range of human health issues since its development in 2012.

Human genome editing is already widely used in basic research and is in the early stages of development and testing for treatments that affect only individual patients, without affecting genes passed onto their offspring.

“It would allow you to take cells from patients who carry genetic diseases and fix the bad mutations,” said Janet Rossant, a senior scientist at Toronto’s Hospital for Sick Children, the Canadian representative on the committee.

For instance, genome editing could be used to treat such genetic diseases as sickle cell anemia and thalassemia, Rossant said.

“That’s called somatic genome editing. You’re not changing it forever (to affect future generations), you’re just changing it for that patient.”

More contentious is the notion of “germline” editing, in which the sperm, egg or early embryo has its DNA altered. Those changes would be passed onto any children and then to subsequent generations.

Many view germline editing as crossing an “ethically inviolable” line, the report said. Concerns raised include spiritual objections, effects on social attitudes towards people with disabilities, interfering with human reproduction, and possible risks to the health and safety of future children.

“Heritable germline editing has long been the subject of discussion,” committee co-chair Alta Charo, a professor of law and bioethics at the University of Wisconsin-Madison, said during the report’s release in Washington.

“We have now gone to the point where it is possible to imagine a day where it is safe, so we need to confront the concerns and possible benefits. Those concerns range from concerns about risk and benefit … (and) the prospect of multiplying risk because it reverberates down the generations.”

Yet germline editing could provide some parents who carry genetic diseases with their best or most acceptable option for having genetically related children who are born free of these diseases, Charo acknowledged.

Still, the committee said, much more research is needed before germline editing could be tried in humans to prevent such inherited conditions as Huntington’s disease, a progressive and fatal neurological condition that typically begins manifesting symptoms in adulthood. Each child of a parent with Huntington’s has a 50 per cent chance of inheriting the disease.

“Although heritable germline genome editing trials must be approached with caution, the committee said caution does not mean prohibition,” said Rossant.

Even so, in many countries, such research is currently prohibited.

“In Canada, any manipulation of DNA of the germline that would be a genetic alteration to be inherited in the next generation is banned — criminally,” she said.

The U.S. Food and Drug Administration is prohibited from reviewing research in which a human embryo is intentionally created or modified to include a heritable genetic modification, and a number of other countries have signed an international convention that bans germline alterations.

The committee said if such regulations were removed in the future and germline gene editing was permitted, stringent criteria would be needed before clinical trials could go forward, including being restricted to altering genes that were demonstrated to cause or strongly predispose a person and their children to a serious disease or condition.

Rossant suggested most people would agree that if a disabling disease that’s passed from one generation to the next could be safely fixed with gene editing, perhaps it should be done to benefit both an affected individual as well as their future children and grandchildren.

“But where do we draw the line between serious genetic disease and potential genetic enhancement? How do we know it won’t be a slippery slope if we allow these approaches to go forward?” she said.

“How do we set guidelines and regulations so that we don’t see it being used for sports enhancement, for down the road perhaps increasing intelligence or whatever other science-fiction approach you might think of.”

– Follow @SherylUbelacker on Twitter.

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