Gene editing: Panel approval ushers in new era
Last week, an influential American advisory panel supported the “editing” of genes — altering the DNA — that parents pass on to their children, or altering the embryo itself.
With many caveats about when and how, the panel’s report takes a position that gene editing can be done — a milestone in this fraught topic, given concerns about “designer babies” and eugenics.
The panel was appointed by the United States’ National Academy of Sciences and the National Academy of Medicine. The US has traditionally had a strong influence on bioethics policy worldwide.
We have the technology to edit the human genome, cut out parts of it and insert preprogrammed bits of replacement genome. We can do that in adults but we could also possibly alter the genes that children inherit. The technology is still relatively immature but is developing rapidly and the ethical and legal frameworks are struggling to keep up.
Gene editing, which is being done in groups all over the world including in South Africa, involves tweaking adult human cells. This is usually known as somatic gene editing.
But germline editing is different: these tweaks can be passed on.
Editing somatic cells affects only the patient, not their children, the group writes in a report released last week.
“By contrast, germline interventions would be aimed at altering a genome in a way that would affect not only the resulting child but potentially some of the child’s descendants as well.”
To date, there have been no reports of this germline editing on embryos that have resulted in a living child. In 2015, a team of Chinese scientists edited the germlines of “nonviable” human embryos, which are embryos that would not result in a live birth.
Last year, the United Kingdom’s Human Fertilisation and Embryology Authority gave permission for researchers at the Francis Crick Institute to germline edit viable human embryos, which then had to be destroyed after seven days. “The knowledge acquired from the research will be important for understanding how a healthy human embryo develops,” the institute said at the time.
On the one hand, this type of research and its therapeutic applications could treat or prevent genetic diseases or disabilities. In Huntington’s disease, which is a genetic and hereditary disease, a person’s brain cells begin to die, leaving them unable to control their body. Babies with Tay-Sachs disease, another inherited genetic disorder, begin to show the signs of neurological damage at seven months, and they seldom live longer than four years.
Germline editing could offer a future in which parents could correct for these genetic conditions.
On the other hand, there are fears that it could be used to enhance traits in offspring and give rise to an era of “designer babies”.
“Human genome editing holds tremendous promise for understanding, treating or preventing many devastating genetic diseases and for improving treatment of other illnesses,” said Alta Charo, cochair of the report and a professor of law and bioethics at the University of Wisconsin-Madison.
“However, genome editing to enhance traits or abilities beyond ordinary health raises concerns about whether the benefits can outweigh the risks and about fairness if only available to some people.”
The panel set out recommendations for when this technology should be used — which was in cases of dread disease and disability when there was an “absence of reasonable alternatives”.
Opinion is divided on whether this human germline editing would be legal in South Africa.
The National Health Act of 2003 prohibits the reproductive cloning of human beings, but does not specifically stipulate that the genes of a viable embryo may not be edited. For a number of years, academics and health experts have raised concerns that our legislation is too vague and significantly lags scientific capabilities.
“Gene editing is genetic manipulation and the subsequent growing of an embryo would be a form of cloning, since you are producing genetically modified daughter cells through replication,” said Michele Ramsay, director of the Sydney Brenner Institute for Molecular Bioscience at the University of the Witwatersrand.
On the other hand, Professor Michael Pepper, director of the Institute for Cellular and Molecular Medicine at the University of Pretoria, does not see the legislation as an impediment. But the technology is too immature to use on people. “This is still a long way off. There are many ethical and legal issues and perhaps the greatest scientific risk is related to the so-called ‘off-target effects’,” he said.
If the technique is on target, you alter the gene you intend to change; if it is off target, it affects other genes.
In South Africa, researchers are allowed to experiment on human embryos up to two weeks old. After 14 days, the embryos have to be destroyed.
“Currently, we lack legislation on important issues in the area of human genetics and genomics,” said Dr Himla Soodyall, director of the human genomic diversity and disease research unit at the National Health Laboratory Service and Wits university.
The Academy of Science of South Africa, the country’s national science academy, is conducting a consensus study, looking at the ethical, legal and social implications in human genetics and genomics, she said. “Also, we need to have wider public engagement around gene editing so that the public voice on this topic is heard.”