Why we should all embrace gene editing in human embryos

The first report of gene editing in viable human embryos performed in the United States has been published. The landmark study demonstrates that gene editing technology can successfully repair faulty genes in the human germline — a scientific term that refers to sperm or egg cells, zygotes, and embryos.

Correcting gene mutations in the germline is powerful because any such modifications are inherited by subsequent generations in a fixed, self-perpetuating configuration. To many, this represents the Holy Grail of modern medicine.

{mosads}Germline editing contrasts gene therapy and other methods that target somatic cells — all of the body’s non-reproductive, differentiated cells. An individual whose somatic cells have been corrected at a specific gene cannot produce offspring that carry the correction.

The ability to edit genes at the germline level brings immense prospects for human health and welfare. Clinical applications that have only ever existed in science fiction are now within the realm of reality. Scientists have developed basic tools that may soon be used to prevent a myriad of debilitating and fatal genetic diseases including Cystic Fibrosis, Tay-Sachs, certain types of cancer, and hereditary forms of Parkinson’s Disease, Amyotrophic Lateral Sclerosis (ALS), and Alzheimer’s Disease.

Despite the vast potential for good, gene editing for clinical purposes is controversial. Jennifer Doudna, a gene editing pioneer, stated she is “uncomfortable” with the clinical applications of the technology. She and others have previously argued for a moratorium on germline editing citing unknown risks, safety, and efficacy concerns.

However, the latest germline editing report suggests that many of the concerns against future use of gene editing technologies for gene repair in human embryos may be premature and overstated. The study sought to correct a mutated version of the MYBPC3 gene, which causes hypertrophic cardiomyopathy, a heritable disease that leads to sudden cardiac failure, often in young athletes.

The study revealed that co-injecting the CRISPR–Cas9 system and sperm carrying the faulty MYBPC3 into healthy donor eggs corrected the pathogenic mutation. Importantly, the researchers overcame many of the problems associated with editing of human embryos that Chinese teams have experienced since 2015.

By injecting the gene editing system before the first cell division, the researchers discovered that mosaicism — a characteristic of embryos that have a mix of edited and unedited cells — could be avoided. This strategy led to highly precise and accurate editing, as evidenced by the lack of unintended off-target mutations in the embryos’ genomes.  

Progress aside, germline editing is not yet ready for primetime. Further research and considerable technology optimization are essential prerequisites for clinical use. Laws that prohibit clinical trials may be reconsidered, in due course, as the technology develops. That all takes time.

Researchers know this. Unfortunately, scientific progress is frequently susceptible to sensationalism.

Unjustified debates concerning germline editing often conjure up eugenics. Alluring and frivolous claims that reproductive technologies will inevitably be used to create tall, beautiful, superhuman geniuses with superb athletic abilities circulate ad nauseam. The myth of “designer babies” has become an emblem of misinformation.

Never mind that the quest to uncover specific intelligence gene(s) has proven to be an exercise in futility. Research shows that, while heritable, highly polygenic traits — those determined by multiple genes—are often determined by the collective contribution of hundreds of genes. For instance, hundreds of genetic variants in at least 180 genetic loci have been reported to influence height in humans.

Knowledge concerning the genetics of complex polygenic traits is vastly incomplete. The notion that scientists can tinker with a few genes — let alone hundreds of them — simultaneously, and know precisely how such manipulation will affect an individual is simply preposterous at this time. And it will likely remain so during our lifetimes.

That scientific fact favors gradual and thoughtful measures — including legislation and policymaking— to address actual concerns raised by germline editing. Entertaining dubious hypotheticals is a dangerous endeavor. And seeking to ban a technology over far-fetched contingencies is bad policy.

So be skeptical when encountering views that aver humans are entering a Brave New World. Be skeptical when scientific progress is reduced to a Frankenstein-like fable engineered to pollute thoughtful debate. The designer baby canard must be confronted.

We are indeed entering a new exciting world. One in which human ingenuity can and will be used to eradicate disease and suffering by pushing the boundaries of knowledge.

We should all embrace this momentous time in human history.

Paul Enríquez is a lawyer and scientist. His work focuses on the intersection of science and law and has been featured in legal and scientific journals. He explores gene editing as it relates to eugenics and the genetics of human intelligence in his recently published article “Genome Editing and the Jurisprudence of Scientific Empiricism.”

The views expressed by contributors are their own and not the views of The Hill.