That’s really super, supergirl (part 2)

6 12 2018

I spent a fair amount of time in the last post going over the technical aspects of gene transfer, in large part because so much of the concern about the prematurity of Jiankui He’s work centers on those technical aspects. (Ed Yong at The Atlantic offers a terrific roundup of those and other concerns; he also collected a snapshot of initial responses to He’s announcement.)

I want to focus on two, different, questions about germline gene transfer: the point of such gene editing, and what it means for those who’ve been so edited.

First, the point. If your concern is with preventing single-locus (Mendelian) disorders, there’s a much more straightforward way of dealing with the risk: test the embryo for the presence of the lethal genes discard those which test positive (two lethal recessives or one lethal dominant).

This process, known as preimplantation genetic diagnosis, is available at most, if not all, fertility clinics in the US, and generally costs in the low thousands; in fact, some of those who don’t have fertility problems choose to make use of assisted reproductive techs (ART) precisely so the embryos can be tested prior to transfer. If you know you and your partner are carriers for, say, cystic fibrosis, it’s a lot easier simply to transfer “healthy” embryos than to try to edit affected ones.

The upshot is that germline gene transfer for single-locus disorders is unnecessary. (The exception might be for those who create embryos which are all affected, but even then, it might be easier to create new embryos than to edit out problem genes.)

This brings up the question, then, for what germline gene transfer could be necessary, and it appears, at this point, nothing; it could be used only for improvement or enhancement.

Now, I should point out that “enhancement” is looked upon with some suspicion by many, many bioethicists, so using that term is. . . provocative. Still, it’s not unwarranted: He altered a normal (or non-disease) gene in order to enhance the offspring’s resistance to HIV. While it’s questionable as to whether the twins will actually have that greater resistance, the clear intent was create people with a capability they would not otherwise have had.

Otherwise known as enhancement.

I am a skeptic of genetic enhancement, not least because most of our traits are complex or multifactorial. Do you know how many genes are involved in your height? Over 700. Any guesses as to how many are involved in, say, intelligence? Your guess would, at this point, be as good as anyone else’s.

Furthermore, many of our genes are pleiotropic, which means that a single gene may be associated multiple traits. And let’s not even get into epigenetics, which is the study of the process by which environmental factors affect gene expression.

All of this means that attempts to edit our genomes in order to enhance the traits so many express an interest in enhancing (eg, height, intelligence, athletic ability) will not be straightforward. This doesn’t mean that all such edits will fail, but that success is likely far off.

There are some traits which are less complicated, traceable to one or a few genes, so it may be possible to fiddle with those genes, but even then there’d be concerns, as there is with the CCR5 gene He edited, that boosting one aspect of the gene’s expression (resistance to HIV) can cripple another (resistance to West Nile virus).

That germline gene editing may not, strictly speaking, be necessary, doesn’t necessarily mean there’s no point at all to it. Even an enhancement skeptic like me can recognize that not every use is automatically terrible, or that, in the case of an environmental disaster or pandemic, it could actually become necessary for species survival.

But we’re a long way away from knowing enough that such use can currently be justified.

Which brings me to the second point: what happens to those little girls, Nana and Lulu? Are they to be research subjects for the rest of their lives? Will their parents be required to offer them up for study? Will they ever be able to say no to such study? How much of their lives be known? Will they have any control over information about them?

And what about their offspring? Will their own children have to be studied? If, as seems probable, Nana and Lulu are mosaics, then there would certainly be interest in the inheritance of those mixed genomes.

If He’s work is not to be a complete waste, the girls should be studied. But how to balance the need/desire for knowledge about his experiment with their human rights and dignity? After all, they didn’t sign up for any of this.

I should point out that in some ways their birth parallels that of Louise Brown, the first IVF baby. No one knew if creating a human embryo outside of the body and then transferring it back to a woman would result in a healthy child, or whether IVF-offspring would themselves be fertile. (It wasn’t until Louise’s younger sister Natalie, also IVF-conceived, gave birth did we know that IVF babies could make babies the old-fashioned way.) In vitro fertilization (and a variation, intracytoplasmic sperm injection) was an experiment which could have ended in horror; that it didn’t has had the effect of minimizing just how great a leap it was.

So what will happen with Lulu and Nana? If all seems well with them, does that make it all okay? If not, then not?

And, again, how will we know? One of the criticisms of the fertility industry is just how much isn’t known: there is no database of children conceived via ART, nor of women who’ve taken fertility drugs. Yes, it is possible to do research on the health of these women and kids, some of which indicate increased risks to health. Is that work sufficient? It’s been 40 years, and it seems mostly okay; is that good enough?

We can’t go back and retroactively require that all ART babies be surveilled—I’m certainly not suggesting that—but would it make sense, going forward with gene-edited people, to have some way to keep tabs on their health?

Y’all know I’m a privacy crank, so even suggesting some sort of life-long surveillance makes my teeth itch, but if such research is to continue, then a necessary part of that research is information about the people who participated in it. Given that a central tenet of human subjects research protection is the right to withdraw from any study at any time, there’s no ethical way to require people who’ve been gene-edited to submit to lifelong study; it is not out of the question, however, to ask.

Anyway, back to Nana and Lulu, two new people who were created as a science experiment which many of us decry. Would it have been better had they never been born? Better, certainly, had He not plowed past the many cautions to mess with the embryos, but now that the girls are here, well, best to welcome them to the human race.

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