Gene-edited babies feared as impediment to legitimate science
WASHINGTON — Scientists working on the frontiers of medicine fear the uproar over the reported births of geneedited babies in China could jeopardize promising research into how to alter hereditary traits to fend off a variety of disorders.
Researchers are rapidly learning how to edit DNA to fight such conditions as Huntington’s, Tay-Sachs and hereditary heart disease, conducting legally permissible experiments in lab animals and petri dishes without taking the ultimate step of actually creating babies. Now they worry about a backlash against their work, too.
“The alarmists who claimed that scientists won’t behave responsibly in the development of the next generation of gene editing now have ammunition,” said a dismayed Kyle Orwig, a reproductive specialist at the University of Pittsburgh who hopes to eventually alter sperm production to treat infertility.
He said there is a clear public demand for the kind of research he is doing.
A Chinese researcher sent a shock wave through the scientific community this week when he claimed to have altered the DNA of embryos in hopes of making them resistant to the AIDS virus. He reported the birth of twin girls and said there might be another pregnancy resulting from his work.
International guidelines for years have said gene editing that can change human heredity — through altered eggs, sperm or embryos — should not be tested in human pregnancies until scientists learn whether the practice is safe. One fear is that such experiments could inadvertently damage genes that could then be passed on to future generations.
China has ordered a halt to the seemingly underground experiments by researcher He Jiankui and his team.
“This is what we’re afraid of: Not legitimate scientists — it’s crazy people that would just try it without even worrying about consequences,” said Shoukhrat Mitalipov of the Oregon Health & Science University, who is conducting laboratory-only experiments on how to repair gene defects in human embryos.
If the outcry results in more restrictions being added to the current patchwork of rules on what can be studied and how, the field “will be, probably, thrown back for decades,” he added.
The challenge, said Pittsburgh’s Orwig, is to “convince the community that this is one bad apple, but it doesn’t reflect what most people are doing.”
There are multiple kinds of gene editing. Experiments to try to fix damaged genes in children and adults with diseases such as sickle cell are fairly straightforward because that drug-like approach would affect only the patient and not his or her offspring.
Far more contentious is gene editing of the “germline,” or changing genes in such a way that they will be passed through generations. The big ethical question is whether such tinkering should be restricted to genes that can cause otherwise untreatable disorders, or whether medicine should be free to create “designer babies” with specific traits, such as high IQ.
“I do think the public is probably open to pretty clearly therapeutic uses of this kind of thing, to prevent transmission of disease. But there’s significant discomfort, if not complete opposition, to enhancement uses,” said Josephine Johnston, an expert on biomedical ethics and policy at the Hastings Center, a bioethics research institute based in Garrison, New York.
In a poll last summer, the Pew Research Center found most Americans — about seven in 10 — said changing an unborn baby’s DNA to treat a serious disease the child would otherwise be born with would be appropriate. But support dropped sharply when people were told that that would involve studies with embryos.
Just 19 per cent thought gene editing for such things as enhancing intelligence would be appropriate, Pew found.
How to prove that gene editing is safe enough to legitimately try in human pregnancies is a conundrum, said University of Pennsylvania bioethicist Jonathan Moreno. “No regulator follows that child over a lifetime, much less their progeny,” he noted.
Another question for ethicists: Even if it were deemed safe, is gene editing of embryos really needed? Already, families who can afford pricey in-vitro fertilization can pay extra to have the embryos genetically tested — and implant only those free of well-known dangerous mutations.
But such preimplantation diagnosis isn’t an answer for everyone, Johnston cautioned. IVF doesn’t always produce enough embryos for couples to choose among. And as testing uncovers more and more disorders, people will have to understand “there’s not going to be a perfect embryo,” she said.
In Pittsburgh, Orwig sees sperm as offering possibly a more practical first step toward germline editing. Some male infertility is caused by genetic defects that prevent testicular stem cells from properly producing sperm. His team studies infertile men to find culprit genes.
Among his plans: Gene-edit stem cells and implant the repaired ones in infertile mice to see if they produce sperm that lead to healthy baby mice. The technique could be adjusted so the genetic change isn’t necessarily passed on to the next generation, he said.
Young women undergoing certain cancer treatments already can store ovarian tissue in hopes of future pregnancy, and Orwig said that one day, it should be possible to remove, say, a mutation in that tissue that otherwise could spread a family’s breast cancercausing BRCA mutation.
“When societal views change and policies change, we’ll be ready,” he said.