Narrow path charted for editing genes of human embryos

doi:10.1126/science.369.6509.1283

GSTDTAP > 气候变化

DOI	10.1126/science.369.6509.1283
	Narrow path charted for editing genes of human embryos
	Jon Cohen
	2020-09-11
发表期刊	Science
出版年	2020
英文摘要	When He Jiankui announced the creation of the first gene-edited babies in 2018, the work was widely seen as dangerous, unethical, and premature. Two years later, an international committee has concluded that the dangers remain too great for anyone to follow in He's footsteps. But its report, released last week, also lays out rare circumstances that might justify “heritable human genome editing” (HHGE) and calls for a global scientific body to help countries assess future proposals. The committee, organized by the U.K.'s Royal Society and two branches of the U.S. National Academies of Sciences, Engineering, and Medicine, reviewed the latest on CRISPR and other ways to modify DNA and consulted scientists, physicians, ethicists, and patient groups. Its report, which Harvard University genome-editing researcher David Liu calls “thoughtful, balanced, and well-bounded,” emphasizes that making heritable genome changes remains too risky for now. “There are a lot of gaps in our knowledge and further research is needed,” says Kay Davies, a geneticist at the University of Oxford who co-chaired the commission. But Liu is uneasy with the report's analysis of when and how embryo editing might be implemented. “I continue to struggle to imagine plausible situations in which clinical germline editing provides a path forward to address an unmet medical need.” The report largely steers clear of the complex social and ethical implications of creating gene-edited babies. But it does call for an international panel of scientists to assess proposed uses of HHGE, provide regular updates about related technologies, and review clinical outcomes if an edited embryo implanted into a mother is born. It also categorizes uses of HHGE into a hierarchy ranging from potentially justifiable to strictly off limits. The most justifiable use, the commission said, would be helping those rare couples who, even with in vitro fertilization (IVF) and screening of embryos before implantation, have little or no chance of having a baby that does not inherit a genetic condition leading to “severe morbidity or premature death.” A couple in which one partner is homozygous for the Huntington disease mutation is an example; without intervention, their children will inherit the mutation and develop the fatal disease. Genetic diseases that have less serious effects and can be corrected or treated in other ways, such as deafness, rank lower. At the bottom—most taboo in the eyes of the panel—is the use of HHGE for genetic enhancement, creating children who are smarter, better at sports, or resistant to HIV, which was the goal of He's experiments. If HHGE is allowed, the panel said, any embryo edit should only “specifically change one DNA sequence into a specific desired sequence” that is common in “the relevant population.” This means the simplest, most frequently used form of CRISPR, which can cripple genes but does not fix them, should never be used in embryos. The panel also noted there may one day be a way to avoid the danger of unintended “off-target” DNA changes. Scientists have proposed editing the stem cells that produce human sperm or eggs before any embryo is created. Those gametes could then be tested for off-target changes before they are used for IVF. The report's criteria for future use of HHGE are so stringent that “it is a ban on editing the genome of the embryo in principle,” says Denis Rebrikov of Pirogov Russian National Research Medical University, who has pursued a project to correct a deafness mutation in embryos of couples who each have the aberrant gene. (Rebrikov has not moved forward because he is not yet satisfied he can safely edit a human embryo.) Fyodor Urnov, a CRISPR researcher at the University of California, Berkeley, is glad the commission was so restrictive. “The careful guidelines laid out in this report show that the list of problems that could be addressed by such editing is, in fact, quite small,” he says. “It is an open secret in the gene-editing community that human reproductive editing is a solution in search of a problem.”
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/294074
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Jon Cohen. Narrow path charted for editing genes of human embryos[J]. Science,2020.
APA	Jon Cohen.(2020).Narrow path charted for editing genes of human embryos.Science.
MLA	Jon Cohen."Narrow path charted for editing genes of human embryos".Science (2020).