A new cautionary tale for heritable genome editing

A fundamental concern about applying gene editing to human embryos is how to limit the risk of errors, or “off-target” effects.  One makes an edit to change a bad gene’s defect, and presumably prevent the disease the defective gene would cause.  But the current methods to do that, although apparently highly selective, might still make other, unwanted changes as well—with possible deleterious, even disastrous, consequences.

Heretofore, the attention to these “off-target” effects has largely been directed to changes in genes that are separated from the target gene.  However, a recent news item in Nature describes three recent experiments with human embryos in the laboratory, in which large defects were induced in the chromosomes bearing the target gene—that is, right next door.  The difference is a bit like the difference between damage by shrapnel (distant effect) and blowing a 6-foot hole instead of a pinhole (near effect).  The latter is now the new concern.  Apparently, and, for one who does not live the scientific details daily, amazingly, prior analytic techniques were missing the possibility of these big, close-in errors.  “CRISPR gene editing in human embryos wreaks chromosomal mayhem,” the headline reads.  Geez Louise…

The technical details are still to be worked out, but one possibility is that, after the targeted gene is cut by the editing mechanism, the way that repair of the genes is done by the human embryo creates the possibility of introducing errors by copying or shuffling of a big chunk of the gene.  These processes are not fully understood in human embryos, and may be different from what pertains in mouse or other animal embryos, or in single human cells such as egg cells or newly-fertilized eggs.

The big technical message is that a lot is poorly understood and will take a ton of work to sort out before one can be confident that a pregnancy carrying a gene-edited to-be-born human will birth a healthy baby, in the immediate outcome, never mind consequences later in life.  It further suggests that no amount of animal work may lay the matter to rest.  From that it’s hard to avoid the conclusion that many embryos will need to be created, altered, and destroyed for research purposes if heritable human genome editing is to proceed with some assurance of safety.  How long would those embryos have to be kept alive to test?  Quite possibly longer than the few days currently possible and accepted by the scientific community.

Absent that, trying to birth gene-edited children would mean, as this blog said some time ago, that “the babies are the experiment.” 

And, even if one does not grant moral status to the human embryo from the point of conception, one is compelled to seek an accounting of the compelling unmet medical need that supports a careful benefit-risk analysis.  Risks to human subjects—embryos, fetuses, eventually-born babies, women donating eggs, perhaps even women carrying partial pregnancies (to allow study of results from a later point in utero?)—seem substantial, overall costs of the effort raise questions of spending the money better elsewhere in the overall health care of society, and alternative approaches to the diseases in question must all be considered.

Geez Louise.

One other point: the Nature article cites preprints posted, prior to peer review of the science, on the website bioRxiv.  Operated by the outstanding Cold Spring Harbor Laboratory, the website offers authors the chance “to make their findings immediately available to the scientific community and receive feedback on draft manuscripts before they are submitted to journals.”  Open access and public feed back are good, but the general press often picks up these preprints, whose quality may not have been fully vetted, and runs with headlines—kind of like I am doing here, following Nature.  So we must watch this space to be sure that the research is being accurately described and interpreted.  For the moment, the topic of this post can be taken as another example of “something to watch out for.”

A principalist argument against heritable genome editing

In May of 2019 The New Bioethics carried a paper (purchase or subscription required) by Jennifer Gumer of Columbia and Loyola Marymount Universities, summarizing an argument against heritable genome editing (the kind in which an embryo’s genes are edited so that the change will be passed down to the subject’s descendants), based on Belmont principalism.  A brief outline of the argument:

  • Uncertainties about the safety of the procedure make it highly unlikely at best that the principle of nonmaleficence (“first, do no harm”) will be satisfied.  Even if the technique substantially eliminates unintended, “off target” gene changes or mosaicism (some cells have the change, others do not), uncertainty will remain about whether interactions between genes may be altered, potentially beneficial positive effects of the “bad” genes may be lost, or the edited gene may have different effects in different environments.  Further, the edited gene will persist in the human population. 
    • At least, this concern would appear greatly to limit the number of genetic conditions that would be appropriate for heritable editing, to a few where a very discreet genetic abnormality that causes a devastating disease is well understood.  Such limits would almost certainly be unenforceable, as efforts to edit genes that clearly cause disease would be expanded to edit genes that predispose to or increase risks of disease, or event to insert or add genes thought to protect from disease.  The additional complexity of the tasks would further confound attempts to calculate risks.
  • The justice of heritable genome editing could well be limited by:
    • The costs, either in the individual case or more broadly on the health care system because in vitro fertilization would almost certainly be required to carry out the heritable editing;
    • Diversion of resources from dealing with environmental or socioeconomic conditions with greater overall impact on the health of the human population;
    • A bias against people with disabilities may be fostered.
  • If heritable gene editing included efforts to enhance traits perceived desirable, harms could arise from miscalculations about whether such enhancement truly yields a better life (e.g., if one could be genetically altered to require less sleep), or pressures on the offspring to perform up to enhanced expectations, again violating the principle of nonmaleficence.
  • Efforts at enhancement would create eugenic pressure to extend the enhancement widely through the population, and/or create a split-class society of (presumably wealthy) genetically enhanced “haves” and unenhanced “have nots,” violating the principle of justice.
  • Limiting heritable genetic editing to the few cases of single-gene-caused serious diseases would benefit only a few affected individuals and their parents, by helping the latter to have genetically-related, unaffected offspring, while risks such as those outlined above could affect many, either by creating direct risks in the population or indirect risks of lost opportunities from deferral of attention to other health and societal problems.
  • Likewise, an appeal to autonomy fails.  Procreative freedom has not yet been held to include a right to bear a genetically-related child, much less one free of undesired traits, and even if such a right were recognized, it would not be unbounded, but would be subject to limits set by concerns such as well-being of the resulting child and societal concerns.  Moreover, parental exercise of autonomy for heritable gene editing would limit the autonomy of society by potentially exposing others to unintended risks without their consent, and would limit the autonomy of gene-edited descendants, whose genomes would be determined at least in part by the decisions of their ancestors.

Thus, in brief, runs the argument.  Like the utilitarian argument summarized in my February 6 post, these contemporary discussions are important to review from time to time.  Further perspectives and analysis to follow in future posts.

An argument for heritable genome editing

Some weeks ago, a utilitarian perspective in favor of heritable genome editing was published (purchase or subscription required to read).  In it, the author, Kevin Smith of Abertay University in the United Kingdom, begins with a general defense of utilitarianism, the ethical philosophy that what is morally good is what produces the greatest good for the greatest number, as opposed to alternative ways of judging that invoke duty, principles, God’s law, or virtues.  In the process, he comments that ethicists who do not consider themselves utilitarian often employ risk-benefit or cost-benefit analyses in making particular judgments.  “We’re all utilitarians now,” as it were.   Smith then proceeds to make a case by a utilitarian, for utilitarians, in favor of pursuing heritable genome editing.  Key points:

  • Genetic editing will technically improve, reducing if not eliminating risks and broadening the ability not only to eliminate genetic disease but also to enhance complex genetic traits and correct mutations that increase risk for disease.  He envisions a day when correcting gene editing errors will readily be reversible by further editing (an “undo” function, as it were).  Consequently, we should anticipate that heritable genome editing will provide many benefits but few harms.
  • Early adoption of technologies is generally beneficial in the end, as, he argues, was the case with IVF, because to delay is to put off the benefits.  In the case of heritable genome editing, we won’t know how well it works without forging ahead.  Nonetheless, the editing of embryos leading to the birth of the edited twins in China in late 2018 was a bit reckless, and the reaction threatens to regrettably and unnecessarily retard progress.
  • Preimplantation genetic diagnosis (PGD) is not a preferable option because some genetic diseases cannot be avoided with PGD (i.e., if all IVF embryos are affected, so there is no unaffected embryo to select) and, more importantly, any additional risk from heritable genome editing is likely to be limited to a relatively few cases in the relative short term, while ultimately yielding much larger benefits to a larger number, justifying the greater risk to some.  (This, I suppose, could be considered crudely analogous to the accepted human research principle that risks to subjects may be acceptable if potential benefits to society—e.g., in development of a candidate new medicine—are possibly greater.  It’s OK for some people to get sick from too high a dose of an experimental drug, for example.)
  • Heritable genome editing should be used soon, because doing so will hasten the first celebrated successes, which will supercharge public support to expand the use of the technology.
  • Adoption is an important alternative, because it increases the happiness of an existing individual, the adoptee, instead of the more speculative prospect of a healthy new person without disease from a mishap from the gene editing.  But if a couple chooses not to adopt, preferring to have a genetically-related offspring, they should not be denied the opportunity if one is possibly available.
  • In general, more new people means more overall happiness for the human race in general, because the new people are more likely to be happy and not, and at least not diminish the happiness of other existing people in the progress.  (This seems to take for granted that heritable genome editing will not cause a detrimental population explosion—which, indeed, seems pretty unlikely.)
  • Having a child produces more happiness for all involved than not having one.
  • Having a genetically related child is better than having one that is partly unrelated, as would be the case with a child conceived using sperm or egg donation from a donor without a genetic disease to be avoided.
  • In cases where a couple simply could not avoid their naturally-conceived child having a bad genetic disease, to go ahead and conceive such a child would entail suffering for the child and parents, and the moral benefits of suffering are overrated.
  • The upside of heritable genome editing—i.e., the potential for human enhancement—is huge.

Many of these points are reasonable as far as they go.  Where this sort of argument leaves one unsatisfied is in the high optimism for technical success without unintended consequences; conceiving the risk-benefit relationship as if it can readily be calculated with confidence; disregard for broad consequences for how we understand ourselves, our begetting, and how we should receive fellow humans who are less than fully whole, physically; and, in some cases, the potential for alternative treatments.

Smith rejects a “precautionary” approach as too timid, but still concludes that maybe we should wait a bit, for the reaction to the Chinese twins’ birth to wear off and for scientist to be able to marshal further their technical case. 

Discussion to follow in future posts.

Controlling gene editing

The title does not mean societal or legal control of gene editing technology.  Rather, it speaks of controlling, or shutting off, a specific gene editing process.  In retrospect, it had to be the case that there is a resistance, or control, mechanism for the CRISPR system, the gene-editing machinery that functions as a way for bacteria to resist invasion by viruses.  An engaging essay in Nature this week discusses this on a level accessible to one who, like me, is not a technical specialist in the field.  Briefly, a few years ago a grad student at UC/San Francisco discovered cases in which the CRISPR system was ineffective in certain bacteria.  Following up led to the discovery of some 50 proteins that can act as “kill switches” for CRISPR.

On a surface level, the implications are clear—learn how to deploy these proteins and one can monitor one’s gene editing efforts for unwanted effects, or for spinning out of control, and if things haven’t gotten too far out of hand, one could turn things off—have an antidote, as it were.

Suppose at some future date that someone were being treated with a gene editing approach for a genetic disease, and things start happening suggesting that other genes than were intended to be the target were being altered.  Presumably one could intervene to treat or prevent the consequences.  Or suppose that genes were being edited to control a certain pest, like malaria-causing mosquitoes.  Presumably there could be an intervention to try to stop the process.

That’s a pretty superficial discussion, but technical experts in the field are trying to learn how to use these “kill switches” to control their gene-editing efforts. 

The also-superficial implication seems clear: these efforts should be understood, and applied in laboratory systems, then perhaps in “somatic” gene editing (treating an existing person for a genetic disease) BEFORE attempts are made to edit human embryos, whether the embryos are intended for gestation or birth or not.  Until things are MUCH more fully understood, there should be no direct work on heritable genome editing.

Chastening and enthusiasm about genome editing

A writer in Nature says that China sent a “strong signal” by punishing He Jiankui and two colleagues with fines, jail times, and bans against working again in human reproductive technology or applying for research funding.  (They lost their jobs as well and may not be able to do research work, presumably in any field, in a Chinese institution again.)  It is encouraging, this writer says, that China took this action demonstrating a commitment to human research ethics.  He and other researchers doing gene-editing work that is not ethically objectionable worry that there may be collateral damage, so to speak, against ANY gene-editing research in China.

Another writer in Nature says cites progress under “appropriate caution” for using gene editing techniques for so-called “somatic” gene editing; that is, editing disease genes in an existing person with that disease, to treat it.  This is, in essence, a form of gene therapy and is ethically permissible under proper research ethical guidelines.  Some clinical trials in progress involve injecting the gene-editing apparatus into a person, while most such trials remove the person’s blood cells, edit them in the laboratory, then re-introduce them into the bloodstream, after which the edited cells are left to mature normally.  The latter approach is particularly attractive to treat genetic blood diseases such as sickle cell anemia.

Both perspectives seem correct, as far as they go—never mind whether Dr. He’s jail sentence fits the crime, as Joy Riley asked on this blog last weekend.  Never mind also whether Dr. He’s research should be published; as Mark McQuain commented, it’s a bit incongruous to want to assess the technical merits of work that should not have been done in the first place.  He linked an opinion in Technology Review that argued, briefly, that because the ethics of editing genes in human embryos is under societal debate, people trying to decide on the ethical merits should be able to assess for themselves whether Dr. He succeeded, technically at what he set out to do.  (The consensus to date seems to be, no, he did not.)   But the role of technical success in assessing the ethical merits of a medical intervention—or, better, an intervention made in the name of medicine—depends on the degree to which the ethical judgment is a matter of making a reasonably reliable of risk and benefit, and the degree to which risk-benefit is a criterion for judging the ethical merits.  And therein, as they say, lies the rub—which I hope to revisit in coming posts.

2020, or 20/20?

Near the end of 2018, He Jiankui was on the world’s stage announcing that he had edited the genome of twin girls, in the hope of making them resistant to HIV. On Tuesday, December 31, 2019, the Wall Street Journal (WSJ) printed a report that Dr. He and two others have been convicted of “illegally practicing medicine related to carrying out human-embryo gene-editing intended for reproduction.” (online version here).

A court in Shenzhen concluded that the defendants had acted for “fame and profit,” when they “deliberately violated the relevant national regulations, and crossed the bottom lines of scientific and medical ethics.” For the crime committed, He received the most severe sentence. In addition to the three-year prison sentence, He is banned for life from “working in the field of reproductive life sciences and from applying for related research grants, “ according to the WSJ.

The Xinhua News Agency also noted that a third genome-edited baby had been born, and that this child, along with the previously born twins, “would be monitored by government health departments.” The WSJ did not state for how long the monitoring would continue. Not only were the children experimental subjects as embryos, but they continue to be subjects as well. Further, these genome effects will affect their progeny, potentially into perpetuity. Additionally, the Smithsonian Magazine reports that in the summer of 2019, He met with “investors to discuss a potential commercial genetic modification clinic in Hainan, which aims to become a ‘world-class medical tourism hub’.”  One might reasonably call this “a crime against humanity,” even if it does not include genocide of humans already born. (For further reading, see David Luban, “A Theory of Crimes Against Humanity”)

In the print edition of the WSJ, alongside the article on He is an article about Pastor Wang Yi of the Early Rain Covenant Church. Pastor Wang was sentenced on 30 December to nine years in prison. His crime was “incitement of subversion of state power and illegal business operations” (online article here).

Consider that a pastor receives a nine-year sentence for an offense against the State; and a scientist, a sentence of three years for a crime against multiple generations, and indeed, humanity. In the year 2020, we could use a check of our understanding of what is important in the life of the world. Would that our vision were 20/20 also.

Can we hop the gene-editing train?

As Joy Riley pointed out on this blog on December 7, the world and the scientific community recently marked, with almost no fanfare, the one-year birthday of “Lulu” and “Nana,” the first (we think) and still only (we think) humans to have had their genes edited heritably—in a way that will be passed on to future generations.  Joy commented these children are “experimental subjects for life,” or, to use the phrase I found and discussed some time ago on this blog, “the babies are the experiment.”  To wit: it is not possible fully to assess and limit the risks of heritable genome editing before actually editing humans.  One must forge ahead.  Even if one were to edit a series of embryos, and abort them at different times during gestation to get a full assessment of their prenatal development, the questions about lifelong effects and effects on future generations would persist. 

And, as mentioned in other posts on this blog earlier this year, there is the issue of “nonphysical” harms to how we understand ourselves and our human existence.

A number of world scientific bodies are assessing, independently of each other, what regulatory safeguards should be instituted, on the assumption that heritable genome editing is something that should be pursued.  Last month, the journal Nature editorialized that efforts by the World Health Organization, US and UK scientific bodies, and a third international commission should not proceed separately (they are all due to report their findings in 2020), but should work together.  The editors apparently think that it would be straightforward, obvious, and right to adopt a moratorium on clinical applications of heritable genome editing, establish an enforced registry for all experimentation in this area, and expand the conversations to include representatives of people with disabilities.  If I read that correctly, it’s hard to disagree.

In the laboratory, things are moving fast and it is well-nigh impossible to keep up with the science or the conversations about it without that work being one’s main occupation.  A recent contribution linked by the Nature editors is called “prime editing” that appears to increase substantially the efficiency of gene editing, raising the prospect of correcting abnormalities associated with the vast majority of genetic diseases.  The relatively naïve, like your present correspondent, might wonder whether this approach could be limited to already-born people with genetic diseases, as treatment, rather than engineer the genomes of the unborn in an apparent attempt to eliminate these abnormalities from the human prospect.

Even thinking about the general public trying to influence where this work leads feels like assuming the role of an old-style hobo, trying to hitch a free ride by jumping onto a moving freight train.  One is liable to fall under the wheels.  But in the case of heritable genome editing, you’re likely to get run over anyway.

Experimental Subjects for Life?

More than a year after the birth announcement of genome-edited babies in China, we are only slightly more informed of He Jiankui’s experimentation, the results of which are named “Lulu” and “Nana.” Although apparently approached, neither Nature nor the Journal of the American Medical Association (JAMA) chose to publish He’s work. Antonio Regalado reported on an unpublished manuscript in “China’s CRISPR babies: Read exclusive excerpts from the unseen original research” in Technology Review on 3 December 2019. The Technology Review article includes not only excerpts of the manuscript from He, but also reactions from Stanford law professor Hank Greely; University of California—Berkeley’s gene-editing scientist Fyodor Urnov; the scientific director of Eugin assisted reproduction clinics, Rita Vassena; and reproductive endocrinologist Jeanne O’Brien, from Shady Grove Fertility.

Regalado summarizes some of the problems with Chinese experiment as follows:

 . . . key claims that He and his team made are not supported by the data; the      babies’ parents may have been under pressure to agree to join the experiment; the supposed medical benefits are dubious at best; and the researchers moved forward with creating living human beings before they fully understood the effects of the edits they had made.

Greely points out the lack of “independent evidence” of the claims made in the paper. Urnov labels the paper’s claim of reproducing the usual CCR5 variant “a deliberate falsehood,” and calls the statement about the possibility of millions being helped through embryo editing “equal parts delusional and outrageous.” O’Brien’s concerns include the possibility of coercion of the couples involved, and, noting the social stigma of HIV-positivity in China, she poses the question of whether this was a genetic fix for a social problem. Certainly, the Chinese experiment raises many questions, including how a culture views children. Are children gifts to be received or projects to be completed? Is it appropriate to subject children to experimental research because we can? One of the quotes from the paper reads, “we have made a follow-on plan to monitor the health of the twins for 18 years and hope to then reconsent for continued monitoring through adulthood.”

We would be remiss if we thought that China alone plans to remake humanity. Vassena is quoted regarding He’s study:

Unfortunately, it reads more like an experiment in search of a purpose, an    attempt to find a defensible reason to use CRISPR/Cas9 technology in human embryos at all costs, rather than a conscientious, carefully thought through, stepwise approach to editing the human genome for generations to come.  As the current scientific consensus indicates, the use of CRISPR/Cas9 in human embryos destined to give rise to a pregnancy is, at this stage, unjustified and unnecessary, and should not be pursued.

Vassena, who directs a fertility enterprise, it should be noted, appears comfortable with impacting the human genome for generations to come:  It just needs to be a “reflective” and “mindful” approach. That is chilling. Would she, or the study’s authors, or Greely, or Urnov, or O’Brien sign up to be a science experiment for the rest of their lives? I would not consent—not for myself nor for my children—no matter how “reflective” or “mindful” the researcher happened to be.

Finally, “Lulu” and “Nana” should be known as more than the results of someone’s laboratory experiment. They are human beings, not laboratory rats or cells under a microscope to be studied at the will and convenience of the experimenters.

Giving thanks for life

The “bio” in bioethics means life. Although it includes other types of life the focus of bioethics is on human life. The announcement a year ago of human infants born in China after their genes had been edited has caused us to think this year about how human life should come into being.

The story in Genesis of the creation of humans tells us some things about who we are. We learn that we are created beings made from the material substance of creation with the breath of life breathed into us by God. We are made to be male and female and complement each other. When we come together in marriage, we have been given the ability to bring new human beings into the world as a result of our union as one flesh. Each new child is given to us as a gift from God. We also learn that God made us in his image so that we are intended to reflect his glory in the world we have been given to steward. That sets us apart from other created life and puts great value on every human being.

How does all this impact how we think about how we bring new human lives into the world? It means we should remember that each new child is a gift from God who should be accepted unconditionally. Children are not intended to be something we make to fulfill our own desires. Each new human being from the very beginning of his or her life has great value. It means we should hesitate to modify the genetics of a new human being to give that child the genes that we think are best. It also means that we should show great respect to any human being who is a subject of research. Human subject research can be very important, but the subjects should enter in voluntarily giving of themselves as a gift to others. When we do research on human beings who are not able to volunteer, the research should cause no more than minimal harm. We should not see human embryos as a disposable resource for research.

As our family travels to our home to celebrate Thanksgiving together this year, I am thankful for each of their lives. I am thankful for my parents who brought me into this world and nurtured me both physically and spiritually. I am thankful for my wife whom God has given to me as a faithful partner and the children God gave to us. I am thankful for the spouses God gave to them and the children they have been given. Above all I am thankful to the God who gives us life.

Skepticism about polygene scores to select for IQ and height

One caution when objecting to the prospect of heritable human gene editing is to take care not to overestimate what it technically possible.  That is, an all-too-easy argument is that attempts to edit a disease gene will lead, by momentum if nothing else, to “designer babies,” with children not just being genetically selected but in fact engineered in great detail for traits like attractiveness, athletic prowess, height, and intelligence.  This contributor to this blog has repeatedly taken the position that heritable human gene editing is a project that fundamentally alters the way we see ourselves and each other; that divides the human race into “actors” and “acted upons;” that has no prospect of prospectively assessing long-term, unintended consequences, to an individual subject, subsequent generations, or society at large; and that fortifies a perspective of admitting to the human race only those members we want to admit.

Along the way, we must keep in mind that “designer babies” are not likely to be feasible in the foreseeable future.  One recently-reported case in point is a study by scientists at the Hebrew University of Jerusalem.  A preprint (in advance of publication in a peer-reviewed journal, it is said) is publicly available here.  I daresay the details will be inaccessible to all but specialists in genetics, but a summary of key points is provided by a technical writer at a website called GenomeWeb.  In brief, some of those points:

  • A score based on assessment of multiple genes has previously been suggested to explain only about 5% of the difference between individuals in IQ (300,000 people genetically tested) or 25% in height (700,000 people tested).
  • These researchers tested about 1000 people, and considered about 15,000 genetic variations.
  • They looked at offspring of actual couples and also “simulated” matches for about 500 would-be couples made from individuals for whom they had genomic data.
  • Of note, they appear to have looked at “SNPs,” or “single nucleotide polymorphisms,” which are relatively easy to catalog across the 30,000 or so human genes, and which themselves run into the hundreds of thousands across those genes, but SNPs are far from the whole genetic story.  Larger differences in genes, or how those genes are translated into biological traits, is much more complex to assess.
  • They surmised that, if their score were used to try to predict height, the average gain would be about 2.5 cm (about one inch), with a range of 1-6 cm.  If used to predict IQ, the average gain would be about 2.5 points, with a range of 1-7 points.
  • Then they also looked at 28 actual families with lots of kids, from 3 to 20 (!).
  • For the actual families, the score predicted to cause the tallest child did so for only 7 of the 28 families, and the highest scoring child was actually shorter than average in the family in 5 of the 28 families.  No attempt to assess IQ for these real families, apparently.
  • They point out other reasons why trying to select for IQ might be problematic—potential association with autism and anorexia, for example, as well as just general complexity.
  • They suggest that for most people undergoing IVF, and creating fewer than 10 embryos in the process with less than 100% success after implantation in the womb, the odds are not good for making a reliable forecast of an offspring’s height or IQ.
  • They make these points without commenting more broadly on the ethics or policy wisdom of allowing or encouraging heritable genome editing to proceed.

A complex story, and a developing one, to be sure, but one should not be too quick to accept grandiose promises for predicting complex traits based on genetics.  At least for now, those appear to be rather “ahead of the puck,” shall we say.