Is Finding Out Your Baby’s Genetics A New Responsibility of Parenting?
Hours after a baby is born, its heel is pricked with a lancet. Drops of the infant's blood are collected on a porous card, which is then mailed to a state laboratory. The dried blood spots are screened for around thirty conditions, including phenylketonuria (PKU), the metabolic disorder that kick-started this kind of newborn screening over 60 years ago. In the U.S., parents are not asked for permission to screen their child. Newborn screening programs are public health programs, and the assumption is that no good parent would refuse a screening test that could identify a serious yet treatable condition in their baby.
Learning as much as you can about your child's health might seem like a natural obligation of parenting. But it's an assumption that I think needs to be much more closely examined.
Today, with the introduction of genome sequencing into clinical medicine, some are asking whether newborn screening goes far enough. As the cost of sequencing falls, should parents take a more expansive look at their children's health, learning not just whether they have a rare but treatable childhood condition, but also whether they are at risk for untreatable conditions or for diseases that, if they occur at all, will strike only in adulthood? Should genome sequencing be a part of every newborn's care?
It's an idea that appeals to Anne Wojcicki, the founder and CEO of the direct-to-consumer genetic testing company 23andMe, who in a 2016 interview with The Guardian newspaper predicted that having newborns tested would soon be considered standard practice—"as critical as testing your cholesterol"—and a new responsibility of parenting. Wojcicki isn't the only one excited to see everyone's genes examined at birth. Francis Collins, director of the National Institutes of Health and perhaps the most prominent advocate of genomics in the United States, has written that he is "almost certain … that whole-genome sequencing will become part of new-born screening in the next few years." Whether that would happen through state-mandated screening programs, or as part of routine pediatric care—or perhaps as a direct-to-consumer service that parents purchase at birth or receive as a baby-shower gift—is not clear.
Learning as much as you can about your child's health might seem like a natural obligation of parenting. But it's an assumption that I think needs to be much more closely examined, both because the results that genome sequencing can return are more complex and more uncertain than one might expect, and because parents are not actually responsible for their child's lifelong health and well-being.
What is a parent supposed to do about such a risk except worry?
Existing newborn screening tests look for the presence of rare conditions that, if identified early in life, before the child shows any symptoms, can be effectively treated. Sequencing could identify many of these same kinds of conditions (and it might be a good tool if it could be targeted to those conditions alone), but it would also identify gene variants that confer an increased risk rather than a certainty of disease. Occasionally that increased risk will be significant. About 12 percent of women in the general population will develop breast cancer during their lives, while those who have a harmful BRCA1 or BRCA2 gene variant have around a 70 percent chance of developing the disease. But for many—perhaps most—conditions, the increased risk associated with a particular gene variant will be very small. Researchers have identified over 600 genes that appear to be associated with schizophrenia, for example, but any one of those confers only a tiny increase in risk for the disorder. What is a parent supposed to do about such a risk except worry?
Sequencing results are uncertain in other important ways as well. While we now have the ability to map the genome—to create a read-out of the pairs of genetic letters that make up a person's DNA—we are still learning what most of it means for a person's health and well-being. Researchers even have a name for gene variants they think might be associated with a disease or disorder, but for which they don't have enough evidence to be sure. They are called "variants of unknown (or uncertain) significance (VUS), and they pop up in most people's sequencing results. In cancer genetics, where much research has been done, about 1 in 5 gene variants are reclassified over time. Most are downgraded, which means that a good number of VUS are eventually designated benign.
While one parent might reasonably decide to learn about their child's risk for a condition about which nothing can be done medically, a different, yet still thoroughly reasonable, parent might prefer to remain ignorant so that they can enjoy the time before their child is afflicted.
Then there's the puzzle of what to do about results that show increased risk or even certainty for a condition that we have no idea how to prevent. Some genomics advocates argue that even if a result is not "medically actionable," it might have "personal utility" because it allows parents to plan for their child's future needs, to enroll them in research, or to connect with other families whose children carry the same genetic marker.
Finding a certain gene variant in one child might inform parents' decisions about whether to have another—and if they do, about whether to use reproductive technologies or prenatal testing to select against that variant in a future child. I have no doubt that for some parents these personal utility arguments are persuasive, but notice how far we've now strayed from the serious yet treatable conditions that motivated governments to set up newborn screening programs, and to mandate such testing for all.
Which brings me to the other problem with the call for sequencing newborn babies: the idea that even if it's not what the law requires, it's what good parents should do. That idea is very compelling when we're talking about sequencing results that show a serious threat to the child's health, especially when interventions are available to prevent or treat that condition. But as I have shown, many sequencing results are not of this type.
While one parent might reasonably decide to learn about their child's risk for a condition about which nothing can be done medically, a different, yet still thoroughly reasonable, parent might prefer to remain ignorant so that they can enjoy the time before their child is afflicted. This parent might decide that the worry—and the hypervigilence it could inspire in them—is not in their child's best interest, or indeed in their own. This parent might also think that it should be up to the child, when he or she is older, to decide whether to learn about his or her risk for adult-onset conditions, especially given that many adults at high familial risk for conditions like Alzheimer's or Huntington's disease choose never to be tested. This parent will value the child's future autonomy and right not to know more than they value the chance to prepare for a health risk that won't strike the child until 40 or 50 years in the future.
Parents are not obligated to learn about their children's risk for a condition that cannot be prevented, has a small risk of occurring, or that would appear only in adulthood.
Contemporary understandings of parenting are famously demanding. We are asked to do everything within our power to advance our children's health and well-being—to act always in our children's best interests. Against that backdrop, the need to sequence every newborn baby's genome might seem obvious. But we should be skeptical. Many sequencing results are complex and uncertain. Parents are not obligated to learn about their children's risk for a condition that cannot be prevented, has a small risk of occurring, or that would appear only in adulthood. To suggest otherwise is to stretch parental responsibilities beyond the realm of childhood and beyond factors that parents can control.
Friday Five Podcast: New drug may slow the rate of Alzheimer's disease
The Friday Five covers important stories in health and science research that you may have missed - usually over the previous week, but today's episode is a lookback on important studies over the month of September.
Most recently, on September 27, pharmaceuticals Biogen and Eisai announced that a clinical trial showed their drug, lecanemab, can slow the rate of Alzheimer's disease. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend and the new month.
Listen on Apple | Listen on Spotify | Listen on Stitcher | Listen on Amazon | Listen on Google
This Friday Five episode covers the following studies published and announced over the past month:
- A new drug is shown to slow the rate of Alzheimer's disease
- The need for speed if you want to reduce your risk of dementia
- How to refreeze the north and south poles
- Ancient wisdom about Neti pots could pay off for Covid
- Two women, one man and a baby
Could epigenetic reprogramming reverse aging?
Ten thousand years ago, the average human spent a maximum of 30 years on Earth. Despite the glory of Ancient Greece and the Roman Empire, most of their inhabitants didn’t surpass the age of 35. Between the 1500s and 1800, life expectancy (at least in Europe) fluctuated between 30 and 40 years.
Public health advancements like control of infectious diseases, better diet and clean sanitation, as well as social improvements have made it possible for human lifespans to double since 1800. Although lifespan differs widely today from country to country according to socioeconomic health, the average has soared to 73.2 years.
But this may turn out to be on the low side if epigenetic rejuvenation fulfills its great promise: to reverse aging, perhaps even completely. Epigenetic rejuvenation, or partial reprogramming, is the process by which a set of therapies are trying to manipulate epigenetics – how various changes can affect our genes – and the Yamanaka factors. These Yamanaka factors are a group of proteins that can convert any cell of the body into pluripotent stem cells, a group of cells that can turn into brand new cells, such as those of the brain or skin. At least in theory, it could be a recipe for self-renewal.
“Partial reprogramming tries to knock a few years off of people’s biological age, while preserving their original cell identity and function,” says Yuri Deigin, cofounder and director of YouthBio Therapeutics, a longevity startup utilizing partial reprogramming to develop gene therapies aimed at the renewal of epigenetic profiles. YouthBio plans to experiment with injecting these gene therapies into target organs. Once the cargo is delivered, a specific small molecule will trigger gene expression and rejuvenate those organs.
“Our ultimate mission is to find the minimal number of tissues we would need to target to achieve significant systemic rejuvenation,” Deigin says. Initially, YouthBio will apply these therapies to treat age-related conditions. Down the road, though, their goal is for everyone to get younger. “We want to use them for prophylaxis, which is rejuvenation that would lower disease risk,” Deigin says.
Epigenetics has swept the realm of biology off its feet over the last decade. We now know that we can switch genes on and off by tweaking the chemical status quo of the DNA’s local environment. "Epigenetics is a fascinating and important phenomenon in biology,’’ says Henry Greely, a bioethicist at Stanford Law School. Greely is quick to stress that this kind of modulation (turning genes on and off and not the entire DNA) happens all the time. “When you eat and your blood sugar goes up, the gene in the beta cells of your pancreas that makes insulin is turned on or up. Almost all medications are going to have effects on epigenetics, but so will things like exercise, food, and sunshine.”
Can intentional control over epigenetic mechanisms lead to novel and useful therapies? “It is a very plausible scenario,” Greely says, though a great deal of basic research into epigenetics is required before it becomes a well-trodden way to stay healthy or treat disease. Whether these therapies could cause older cells to become younger in ways that have observable effects is “far from clear,” he says. “Historically, betting on someone’s new ‘fountain of youth’ has been a losing strategy.”
The road to de-differentiation, the process by which cells return to an earlier state, is not paved with roses; de-differentiate too much and you may cause pathology and even death.
In 2003 researchers finished sequencing the roughly 3 billion letters of DNA that make up the human genome. The human genome sequencing was hailed as a vast step ahead in our understanding of how genetics contribute to diseases like cancer or to developmental disorders. But for Josephine Johnston, director of research and research scholar at the Hastings Center, the hype has not lived up to its initial promise. “Other than some quite effective tests to diagnose certain genetic conditions, there isn't a radical intervention that reverses things yet,” Johnston says. For her, this is a testament to the complexity of biology or at least to our tendency to keep underestimating it. And when it comes to epigenetics specifically, Johnston believes there are some hard questions we need to answer before we can safely administer relevant therapies to the population.
“You'd need to do longitudinal studies. You can't do a study and look at someone and say they’re safe only six months later,” Johnston says. You can’t know long-term side effects this way, and how will companies position their therapies on the market? Are we talking about interventions that target health problems, or life enhancements? “If you describe something as a medical intervention, it is more likely to be socially acceptable, to attract funding from governments and ensure medical insurance, and to become a legitimate part of medicine,” she says.
Johnston’s greatest concerns are of the philosophical and ethical nature. If we’re able to use epigenetic reprogramming to double the human lifespan, how much of the planet’s resources will we take up during this long journey? She believes we have a moral obligation to make room for future generations. “We should also be honest about who's actually going to afford such interventions; they would be extraordinarily expensive and only available to certain people, and those are the people who would get to live longer, healthier lives, and the rest of us wouldn't.”
That said, Johnston agrees there is a place for epigenetic reprogramming. It could help people with diseases that are caused by epigenetic problems such as Fragile X syndrome, Prader-Willi syndrome and various cancers.
Zinaida Good, a postdoctoral fellow at Stanford Cancer Institute, says these problems are still far in the future. Any change will be incremental. “Thinking realistically, there’s not going to be a very large increase in lifespan anytime soon,” she says. “I would not expect something completely drastic to be invented in the next 5 to 10 years. ”
Good won’t get any such treatment for herself until it’s shown to be effective and safe. Nature has programmed our bodies to resist hacking, she says, in ways that could undermine any initial benefits to longevity. A preprint that is not yet peer-reviewed reports cellular reprogramming may lead to premature death due to liver and intestinal problems, and using the Yamanaka factors may have the potential to cause cancer, at least in animal studies.
“Side effects are an open research question that all partial reprogramming companies and labs are trying to address,” says Deigin. The road to de-differentiation, the process by which cells return to an earlier state, is not paved with roses; de-differentiate too much and you may cause pathology and even death. Deigin is exploring other, less risky approaches. “One way is to look for novel factors tailored toward rejuvenation rather than de-differentiation.” Unlike Yamanaka factors, such novel factors would never involve taking a given cell to a state in which it could turn cancerous, according to Deigin.
An example of a novel factor that could lower the risk of cancer is artificially introducing mRNA molecules, or molecules carrying the genetic information necessary to make proteins, by using electricity to penetrate the cell instead of a virus. There is also chemical-based reprogramming, in which chemicals are applied to convert regular cells into pluripotent cells. This approach is currently effective only for mice though.
“The search for novel factors tailored toward rejuvenation without de-differentiation is an ongoing research and development effort by several longevity companies, including ours,” says Deigin.
He isn't disclosing the details of his own company’s underlying approach to lowering the risk, but he’s hopeful that something will eventually end up working in humans. Yet another challenge is that, partly because of the uncertainties, the FDA hasn’t seen fit to approve a single longevity therapy. But with the longevity market projected to soar to $600 billion by 2025, Deigin says naysayers are clinging irrationally to the status quo. “Thankfully, scientific progress is moved forward by those who bet for something while disregarding the skeptics - who, in the end, are usually proven wrong.”