This post is a part of our Bioethics in the News series
By Leonard M. Fleck, PhD
The headline in New York Times Magazine reads: “Scientists can now sequence an entire genome overnight.” This is amazing. It took ten years and $3 billion to do the first mapping of the human genome, all three billion base pairs. Today the entire genome of any individual can be mapped for less than $1000. Why is that important? There are preventative, diagnostic, therapeutic, reproductive, and public health reasons. The public health reasons are most evident with the speed with which all the variants of COVID-19 have been mapped.
Having one’s genome mapped can provide an individual with some foreknowledge of health risks to which they might be vulnerable (always keeping in mind environmental factors linked to inherent genetic risks, also keeping in mind the uncertainty and probabilities associated with the vast majority of health risks identified in this way). The risks of medical harm related to genetic ignorance can be reduced. A family of genes referred to as P450 determine whether we are normal, fast, or slow metabolizers of drugs. If we are fast metabolizers, a normal dose will be metabolized too quickly with diminished effectiveness. If we are slow metabolizers, a normal dose will accumulate to potentially life-threatening levels in some cases. Roughly 7% of 1200 FDA approved medications are affected by actionable germline inherited pharmacogenes. Even more importantly, 18% of outpatient U.S. prescriptions (more than four billion per year) are affected by actionable germline pharmacogenomics.
Whole Genome Sequencing (WGS) can assist future possible parents to determine the best reproductive option if they know they represent specific genetic risks to future possible children, e.g., if each were a carrier for a mutated cystic fibrosis gene. In addition, WGS can be used to make accurate diagnoses of very rare disorders that would otherwise require harmful, invasive, diagnostic odysseys. This will be very important in the context of infants in the NICU or children in the PICU.
I remind students that unlike normal medical tests that only yield information about the person who has the test, genetic tests tell us about genetic features of a range of close relatives. Hence, if a genetic test identifies a serious health vulnerability in me, that information can be used to alert other family members of that same vulnerability of which they might otherwise have been ignorant (and which might well be medically manageable before clinical symptoms emerge that might then suggest an irreversible disease process). The therapeutic potential of WGS is most evident today in the case of metastatic cancer. WGS can provide base-pair resolution of an entire tumor genome in a single run, thereby revealing the unique mutations and genomic alterations in the cancer tissue. This will often allow the identification of a targeted cancer therapy, such as imatinib, that targets the distinctive genetic features of a cancer, such as chronic myelogenous leukemia.
In the reproductive context WGS can be used as a non-invasive prenatal screening tool to offer a comprehensive assessment of the fetus. Likewise, WGS could be used at birth as a screening tool to offer a more comprehensive assessment of the infant than the current gene panel, which is only looking for fifty-six rare genetic disorders. This increases the opportunities for timely therapeutic interventions, when available.
Given all these potential therapeutic benefits, what would be the potential ethical challenges? Cost is an issue that raises health care justice problems. Though the sequencing itself costs less than $1000, the analysis, interpretation and counseling bring the cost to $3000 (though in the case of cancer treatment the cost will be $10,000). Few health insurers cover these costs. Should access to WGS then be publicly funded, as a matter of health care justice, perhaps as part of a basic benefit package guaranteed to all? If all 330 million Americans wanted WGS, the cost would be $990 billion. Would that be either a wise or just use of limited health care resources, given all sorts of other unmet health care needs in our society?
One of the main rationales for doing WGS is preventive, i.e., to identify significant health vulnerabilities whose risk of actualization can be reduced by behavioral change. However, the critical question is whether we can be very confident that most patients would commit to the required behavioral changes. Available medical evidence suggests pessimism in this regard, which would imply that WGS with this expectation represented a poor use of social resources. No one believes McDonald’s business plans are threatened by WGS.
If WGS is used to replace current neonatal screening practices, are the privacy rights of newborns put at risk, given later in life genetic vulnerabilities that would be revealed? Would these concerns be mitigated if only medically actionable information were revealed to parents, all other information being set aside until that child reached adulthood? However, what exactly is the scope of “medical actionability?” That child might be vulnerable to some serious genetic disorders much later in life. This would not be a concern for the child as a child. But that child might have older relatives for whom this information would have considerable potential relevance. What are the ethical issues associated with either revealing or failing to reveal that information to potentially “at-risk” relatives?
A very important feature of genetic information gleaned from neonatal WGS (and all WGS for that matter) is that the vast majority of that information will be either of unknown or highly uncertain significance. This will be especially true because of the thousands of mutations that would be part of anyone’s DNA. For parents of a newborn, such uncertainty could be distressing for years and years. However, there is also the uncertainty associated with the responsibilities of primary care physicians in this regard. Who is supposed to have responsibility for tracking changes in genetic knowledge regarding those genetic variations in an individual as medical research advances? And who would be responsible for conveying this new information to parents or adult children, and judging what should be told and when? This is a very complex medical information management problem, relative to which current physician complaints regarding the electronic medical record would fade into insignificance.
Let us assume that WGS is going to be done more thoughtfully and more parsimoniously, such as a diagnostic or therapeutic context where such information would be most useful. What will still happen is the discovery of all sorts of incidental genetic information, sometimes with frightening potential consequences. Imagine this bit of medical dialogue: “Mr. Smith, we were looking for the genetic roots of your heart disease (which we found), but we also discovered your genetic vulnerability to an early-onset form of dementia.” Many patients would not want to know this. How is a physician supposed to know what a patient does or does not want to know in this regard?
Finally, WGS could generate new problems of health care justice. Imagine that the incidental finding in the prior paragraph was a 10% lifetime risk of some serious but treatable cancer. I personally would not be especially distressed by such a finding. However, other individuals might be especially anxious and demand all manner of expensive diagnostic tests on a semi-annual basis to rule out any indications of disease initiation. Would that individual have a just claim to such resources at social expense?
To return to the title of this essay, perhaps the fact that WGS is quick, easy to do, and relatively inexpensive is insufficient reason to justify the promiscuous promulgation at social expense of this technology. Perhaps more thoughtful social and professional deliberation regarding the issues identified in this essay would yield less ethically fraught uses of WGS. Then again there could be the 2030 version of the electronic medical record with room for terabytes of genetic information and thousands of new tabs and subtabs!
Leonard M. Fleck, PhD, is Professor in the Center for Bioethics and Social Justice and the Department of Philosophy at Michigan State University.
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More Bioethics in the News from Dr. Fleck: Religious Coercion of Physicians: Whose Conscience Is It Anyway? Health Care and Social Justice: Just Take Two Aspirin for Your Tumor If You Cannot Afford Your Cancer Care; Medicare For All: This Is Going to Hurt; Greed Is God: The Divine Right to Avaricious Drug Pricing; Gene Editing: God’s Will or God’s Won’tClick through to view references