Is gene editing going too far? Ethical boundaries of CRISPR debated

For years, bioethicists have anxiously called for open discussion of gene editing, a developing technology to modify human DNA that proponents say could help cure debilitating diseases, while critics caution that the tools are rushing headlong into the future without considering side-effects and ethical concerns. 

Those concerns intensified sharply last spring, when a team at China's Sun Yat-sen University altered inheritable genes in non-viable human embryos for the first time in history, such a shocking development that leading international journals Science and Nature refused to publish the research. 

On Tuesday, scientists from the around the world convened for the first international summit to debate the benefits and risks of gene editing. The conference, held at the National Academies of Science in Washington, and co-hosted by the Chinese Academy of Sciences and the Britain's Royal Society, will run from Dec. 1-3. 

"We sense that we are close to being able to alter human heredity," Nobel laureate David Baltimore, of the California Institute of Technology, said as he opened the meetings Tuesday. ''This is something to which all people should pay attention," he told listeners from more than 20 countries. 

There are a few ways to edit genes inside living cells, "cut and paste"-style, but the field has taken off with CRISPR-Cas9, a method so readily accessible that "amateur biologists working in converted garages or community laboratories are starting to dabble," according to Nature. 

That's the technique used by the Chinese team, headed by Junjiu Huang. Although gene-editing therapies for treating disease have been used twice before, the Chinese embryo experiments were the first to involve genes that could potentially be passed on to the next generation, although they intentionally used defective embryos in an effort to avoid ethical dilemmas.

But that wasn't enough to avoid all controversy. Many scientists are concerned about CRISPR-Cas9's imperfect precision, although MIT researcher Feng Zhang, who is attending the summit, has just announced changes to the genome editing system, tweaks which he says can significantly reduce the chance of error. 

Dr. Zhang, like most scientists and the Sun Yat-sen team, cautions that technological advancements still have not made gene editing safe for clinical use. "We certainly don’t see this as a magic bullet," he said in an MIT statement.

Research proponents see an exciting opportunity to prevent disease in gene editing technology – a tool to stop what have been deemed inheritable diseases in by editing parents' genes, which would then be passed on to future children. They warn that if mainstream science doesn't support such research, it will fall into less capable or less well-intentioned hands.

But for now, support for "germline" editing, as changes to reproductive cells are called, has somewhat scant support. The White House, for instance, has cautioned that "altering the human germline for clinical purposes is a line that should not be crossed at this time," a stance reiterated at the DC summit by the White House senior science advisor John Holdren. 

For many opponents, the science is just too unpredictable, at least for now. If the germline is edited, any changes, whether beneficial, harmful, or unknown, could impact multiple generations. 

"This is evolving rapidly because it's so easy to use. But it's easy to use in the sense of making something happen. It's not easy to use necessarily in the sense of making what you want to have happen," University of Wisconsin biologist Dr. Kate O'Connor-Giles told the Monitor in April. 

That's why researchers have called for international guidelines, starting with discussions like this week's conference. In 2016, an international committee put together by the National Academies' Human Gene-Editing Initiative is expected to release a report. 

International understandings are key, some say, because new developments and applications are likely to spread quickly. Japanese bioethicist Tetsuya Ishii told Nature he suspects countries with high rates of in vitro fertilization, like Japan, might be the first to latch on.

That notion might alarm ethicists who worry about potential for "designer babies," the chance that gene-editing would be used for alternations other than disease therapy. The vast majority of Americans – 83 percent – oppose modifying genes to improve a baby's intelligence, according to Pew surveys. Yet when asked if they oppose genetic changes meant to prevent disease, only 50 percent say that goes too far.

Among respondents with stronger science backgrounds, that number drops slightly: 40 percent oppose such modifications, while 52 percent say they are appropriate. 

This report includes material from the Associated Press.