Recently, a scientific milestone hit the headlines, raising a flurry of excitement and concern.Scientists used a rapidly rising and powerful new gene editingtechnique, CRISPR, to “correct” a genetic mutation linked to aninherited heart condition, in human embryos. The accomplishmentbrings us closer to a day when doctors could eliminate the root causeof certain inherited diseases by modifying human DNA. Along withexcitement, there is a growing awareness of the need to carefullycontrol such technologies that could permanently alterthe human condition.
Thanks to decades ofresearch, we now stand on the verge of what many see as a revolution ingenetic medicine. The newest iteration of gene editing technology,CRISPR, first came onto the scene five yearsago. (CRISPR stands for clustered regularly interspaced shortpalindromic repeats, an accurate but awkward description of one of theproperties that led to the discovery of a way some bacteria have ofresisting virus infection.) Since then – a blink of aneye in the world of scientific research – CRISPR-enabled achievementshave poured forth. A testament to the tool’s incredible versatility andease-of use, it has modified the genomes of crops, laboratory animals,and human cells in a dish. The next naturalstep is to bring our research investments full circle, and use thetechnology to improve human health.
Yet there is muchthat still needs to be done to ensure that the procedures are reliablysafe and effective. For example, we need to know that CRISPR makes theintended repair accurately, and without inadvertentlydamaging other genes that might accidentally trigger cancer, or otherburdensome conditions.
Where CRISPR raisesserious ethical concerns is gene editing in human embryos, anaccomplishment that was reported last week. If the embryos were allowedto develop, the changes would be transmitted to everycell of the future child, including his or her sperm or eggs, andtherefore would be passed on to future generations. The prospects ofthis so-called germline therapy have prompted calls for its delay untilthe ethical and technical issues can be adequatelyaddressed. A relatively safe, well-tested alternative is screening invitro fertilized embryos and implanting only those that are free fromspecific disease-causing mutations.
Questions havealready been raised over the kinds of conditions that should betargeted. Serious genetic diseases that affect children are logicaltargets. But should we treat embryos (at the request of parents)that have an increased risk for cancer or Alzheimer’s disease,conditions that won’t arise until the child has become a mature adult?If it is ethical to protect future children from disease, would it beethical to enhance their intelligence or athleticismif the genetic bases for such traits are found?
Many will recoil atthe possibilities of this sort of control over the biology of ourchildren. Is this “playing God?” Do we have the wisdom to make thesedecisions? Others see primarily golden opportunitiesto reduce the burden of disease and improve the quality of life. Suchdiscussions make it clear is that we, as a society, need to have thesort of regulatory and oversight mechanisms in place to assure that suchpowerful technologies are thoroughly studied,evaluated, and openly debated before they move from the laboratorybench to the clinic.
The investment inbiomedical research has led to a milestone in genome editing, and thereis little question we should benefit from the fruits of that investment.At the same time, this powerful technologymust be appropriately tested and regulated to ensure that it is appliedsafely, sensibly, and equitably.
Dana Carroll is Distinguished Professor of Biochemistry at University of Utah Health and a member of the National Academy of Sciences. Jeffrey Botkin is chief of Medical Ethics and Humanities at University of Utah Health and director of the University of Utah Center for Excellence in the Ethical, Legal, and Social Implications of Genetic Research