Bioethics @ TIU

The goal of human embryonic gene editing is enhancement

Posted August 2nd, 2017 by Steve Phillips

As Jon Holmlund reported in his post last week, research on the editing of genes in human embryos is now being conducted in the United States. The door to doing this research was opened by the consensus report on Human Genome Editing published by the National Academy of Sciences earlier this year. That report encouraged the pursuit of research on gene editing in human embryos and justified that based on the potential benefit of editing human embryos to correct genes for serious human genetic disorders. The report recommended that once basic research could show the reliability of the gene editing techniques it would be reasonable to proceed with human clinical trials as long as those trials involved the correction of genes responsible for serious genetic disorders. They stated that there were significantly more moral concerns about using human genome editing for enhancement and that enhancement should not be pursued until those moral concerns were resolved. Thus, the research currently being done in Portland, Oregon by Shoukhrat Mitalipov (see article in MIT Technology Review) involves creating human embryos with a single gene genetic disorder and then editing the abnormal gene to remove the disorder.

However, the idea that human germline genetic modification should be pursued to correct serious genetic disorders is a flawed concept. The technique used by Mitalipov does not involve treatment of a diseased human embryo, but the creation at the time of conception of a genetically altered embryo. Since the goal of this procedure is not the treatment of a diseased individual, but the creation of a child free of a particular genetic disease for parents who desire such a genetically related child, there is a much simpler and already available means to accomplish that goal. The parents can accomplish that in the large majority of cases by using preimplantation genetic diagnosis (PGD) to select an embryo that does not have the disorder. Since this method is much simpler, involves much less risk, and will undoubtedly be less expensive than gene editing, there would be very little market for embryonic gene editing for parents who are carriers of a serious genetic disorder and desire to have an unaffected child.

Some might suggest that gene editing of embryos with a genetic disorder would be morally preferred to PGD because of the destruction of the embryos who do have a genetic disorder in the process of using PGD. This is based on the human embryo having full moral status which makes the destruction of embryos inherent in the way PGD is used impermissible. However, if human embryos have full moral status, then the research being done to develop human embryonic gene editing is impermissible since it involves destruction of the embryos created for the research.

Since there will be little practical use for human embryonic gene editing in dealing with serious genetic disorders, what will human embryonic gene editing be used for? It will be used for things that cannot be done with PGD. It will be used to create children with genes that the parents do not possess. It will be used for enhancement. Those who promote research on human embryonic gene editing should be honest and admit that it will have little use in the treatment of single gene disorders and that the real reason to develop it is to do enhancement, which they admit is morally problematic.

2 Responses

  1. Steve Phillips says:

    I wrote this post before the research was published yesterday. It was based on preliminary reports that did not give the details that were published. His article indicated that he did not succeed in inserting a corrected gene as he had intended, but that the zygote replaced the deleted abnormal gene with a copy of the normal gene from the mother. It is hard to tell whether this will be a reproducible phenomenon. Most gene editing in other species has involved the insertion of a new gene as he was trying to do. That does not change the assertion that I made that embryonic gene editing will not be used for this type of disease due to PGD being simpler, less risky, and less expensive. It is still true that the primary use of embryonic gene editing will likely be enhancement.

  2. L says:

    I think you misunderstand the results of Dr. Mitalipov’s research. He inserted the CRISPR-Cas 9 system with the guide RNA into the cell to target a mutation in the father’s DNA.

    However, the cell did not use the guide RNA he provided to make the change. It used the mother’s DNA as a template to replace the father’s damaged version. The sharing of maternal and paternal DNA for repair is a normal process in cells that occurs every day.

    Thus, instead of providing an entirely novel sequence to the cell, this technique is more like a guided picking and choosing of the mother’s and father’s DNA. I believe this changes the moral questions related to the technique.

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