WHO Experts Seek Limits To Human Gene Editing Experiments, Health News, ET HealthWorld
Their recommendations, made after two years of deliberation, aim to avoid dishonest scientific experiments with the human genome and to ensure that the appropriate use of gene editing techniques benefits the general public, especially people in developing countries, and not just to the rich.
“I’m very supportive,” said Dr Leonard Zon, a gene therapy expert at Harvard University who was not a member of the committee, but called it a “think tank.” The recent results of gene editing are “impressive”, he said, and the committee’s recommendations will be “very important for therapy in the future”.
The guidelines proposed by the WHO committee were prompted in large part by the case of He Jiankui, a scientist in China who stunned the world in November 2018 when he announced that he had altered the DNA of embryos using CRISPR, a technique that enables precision editing. of genes. Such alterations meant that any changes in the genes would be replicated in every cell of the embryo, including sperm and eggs. And that meant that the alterations, even if they were deleterious instead of useful, would occur not only in babies born after gene editing, but in every generation their DNA was passed down.
Its goal was to modify the DNA of babies in order to make them genetically incapable of contracting HIV from their parents. A Chinese court ruled that he had falsified ethical documents and misled subjects in experiments who failed to realize what his gene editing experiment was. He was sentenced to three years in prison in December 2019.
The fact that such an experiment, known as germline editing, could take place raised the question of how to control gene editing and how to ensure that it is used for the benefit of people. .
WHO standards say the use of He germline editing was unacceptable and that it is irresponsible to even consider using it now. But other types of gene editing are another story.
Scientists are already trying to edit genes to correct the mutation that causes sickle cell disease. The altered gene is believed to be found in the hematopoietic cells of the bone marrow of people with the disease, not in sperm or eggs, so the changes are not passed on from generation to generation. But even this use of CRISPR raises other questions.
The WHO committee has described a made-up scenario where researchers in a wealthy country want to do a clinical trial of sickle cell gene editing in sub-Saharan Africa, where the disease is prevalent. If the trial is successful, the gene editing treatment would be too expensive for everyone, but very few citizens of the country where it is to be tested.
Another hypothetical situation involves an attempt to edit genes to correct a genetic mutation that causes Huntington’s disease, a progressive brain disorder. People who inherit the mutated gene will develop Huntington’s disease with absolute certainty. If the gene editing experiment is successful, maybe it will save them this horrible disease. And because the assembly does not involve sperm and eggs, the changes will not be hereditary.
But it would take years, if not decades, to find out whether study participants whose genes were changed were protected against Huntington’s disease. Participants would not be freed from the terrible fear that, despite gene editing, they could still develop the deadly brain disease.
In such a scenario, the WHO group asked if there were faster ways to assess the effectiveness of the treatment. He also proposed that the researchers take into account the psychological burden of participants who hope to be cured but don’t know for sure.
Still, gene editing is there and shows great promise, the committee said. WHO has launched a registry of ongoing studies and says it already includes 156 experiments involving genes that are not found in sperm or eggs.
The WHO committee stressed that every country should have guidelines to ensure that research is conducted ethically and with appropriate oversight, and with conditions in place to ensure access and social justice. With treatment costs expected to be very high, at least initially, the group said the goal should be to ensure that the benefits of gene editing fairly flow to people around the world.
“It’s not an easy challenge,” said Françoise Baylis, committee member and researcher in medical ethics at Dalhousie University in Halifax, Nova Scotia.