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Ethics Consult: Edit an Embryo's Genome to Prevent Disease?

<ѻýҕl class="mpt-content-deck">— Make the call
Last Updated February 15, 2020
MedpageToday
A computer rendering of an embryo held by a pipette being manipulated with a needle

Welcome to Ethics Consult -- an opportunity to discuss, debate (respectfully), and learn together. We present an ethical dilemma in patient care; you vote on your decision in the case. Next week, we'll reveal how you all made the call, and bioethics experts Alyssa Burgart, MD, MA, and Josephine Johnston will weigh in with an ethical framework to help you learn and prepare.

Amanda, a 25-year-old woman, has received a devastating diagnosis – she carries the mutation for an extremely rare prion disease called (GSS) disease. Her father is currently dying of the disease, and this diagnosis has been her greatest fear. The condition is usually fatal and affects patients from ages 20 to 60. Patients live an average 5 years (range 2-10) after diagnosis. The disease is autosomal dominant, so any family member with one copy of the gene will develop the disease and has a 50/50 chance of passing it onto their offspring.

Amanda faced an ethical dilemma about whether to have biological children and, if she does, whether to use prenatal testing or assisted reproductive technologies to ensure that her children do not carry the disease gene. Due to her religious beliefs, Amanda is opposed to abortion and deeply conflicted about using preimplantation genetic diagnosis (PGD) to select unaffected embryos because she knows that the PGD process would include discarding affected embryos. Amanda and her husband eventually decided to use PGD and have had three children who do not carry the disease gene.

In the future, people in Amanda's position could be offered germline editing so that affected embryos could be modified to have the non-disease gene, and all embryos they create could be transferred for gestation. Babies developing from these germline-edited embryos would not have the disease themselves and would never pass the disease on to future children. This kind of gene editing is different from gene therapy or somatic gene editing, where the affected gene is only changed in certain parts of the body, but not necessarily in the germ cells (eggs and sperm).

There are significant ethical arguments against germline editing. Objections include uncertain benefits of therapy, fear of off-target, unanticipated effects in the genome, and that future generations cannot consent to genomic changes. Scientists and ethicists worry that technology used to justify prevention of serious illness now will help perfect a system leading to designer human enhancements, such as increasing intelligence, height, or other socially advantageous traits. Presumably, such enhancements would only be available to those who can afford them, leading to serious disparities.

Critics of genome editing for serious illness argue that preimplantation genetic diagnosis can already solve this issue. However, germline editing could reduce the need for embryo destruction, by repairing existing embryos, which could satisfy the moral priorities of patients like Amanda.

This case is based on a story from the New York Times: . Gina Kolata's offers an in-depth account of this family's journey.

See the results and what experts have to say.

Save the date: will also be hosting a Twitter Chat with authors Burgart () and Johnston () on Wednesday, February 19, at 4:00 p.m. ET. Follow to join.

, is assistant professor of anesthesia at the Stanford University School of Medicine and core faculty in the . She is a bioethicist at Stanford Healthcare and Lucile Packard Children's Hospital. is director of research and a research scholar at , an independent bioethics research institute in Garrison, New York. She is a New Zealand-trained lawyer and bioethicist and co-editor of .