Can Genetic Testing Help Shed Light on the Autism Epidemic?
Autism cases are still on the rise, and scientists don't know why. In April, the Centers for Disease Control (CDC) reported that rates of autism had increased once again, now at an estimated 1 in 59 children up from 1 in 68 just two years ago. Rates have been climbing steadily since 2007 when the CDC initially estimated that 1 in 150 children were on the autism spectrum.
Some clinicians are concerned that the creeping expansion of autism is causing the diagnosis to lose its meaning.
The standard explanation for this increase has been the expansion of the definition of autism to include milder forms like Asperger's, as well as a heightened awareness of the condition that has improved screening efforts. For example, the most recent jump is attributed to children in minority communities being diagnosed who might have previously gone under the radar. In addition, more federally funded resources are available to children with autism than other types of developmental disorders, which may prompt families or physicians to push harder for a diagnosis.
Some clinicians are concerned that the creeping expansion of autism is causing the diagnosis to lose its meaning. William Graf, a pediatric neurologist at Connecticut Children's Medical Center, says that when a nurse tells him that a new patient has a history of autism, the term is no longer a useful description. "Even though I know this topic extremely well, I cannot picture the child anymore," he says. "Use the words mild, moderate, or severe. Just give me a couple more clues, because when you say autism today, I have no idea what people are talking about anymore."
Genetic testing has emerged as one potential way to remedy the overly broad label by narrowing down a heterogeneous diagnosis to a specific genetic disorder. According to Suma Shankar, a medical geneticist at the University of California, Davis, up to 60 percent of autism cases could be attributed to underlying genetic causes. Common examples include Fragile X Syndrome or Rett Syndrome—neurodevelopmental disorders that are caused by mutations in individual genes and are behaviorally classified as autism.
With more than 500 different mutations associated with autism, very few additional diagnoses provide meaningful information.
Having a genetic diagnosis in addition to an autism diagnosis can help families in several ways, says Shankar. Knowing the genetic origin can alert families to other potential health problems that are linked to the mutation, such as heart defects or problems with the immune system. It may also help clinicians provide more targeted behavioral therapies and could one day lead to the development of drug treatments for underlying neurochemical abnormalities. "It will pave the way to begin to tease out treatments," Shankar says.
When a doctor diagnoses a child as having a specific genetic condition, the label of autism is still kept because it is more well-known and gives the child access to more state-funded resources. Children can thus be diagnosed with multiple conditions: autism spectrum disorder and their specific gene mutation. However, with more than 500 different mutations associated with autism, very few additional diagnoses provide meaningful information. What's more, the presence or absence of a mutation doesn't necessarily indicate whether the child is on the mild or severe end of the autism spectrum.
Because of this, Graf doubts that genetic classifications are really that useful. He tells the story of a boy with epilepsy and severe intellectual disabilities who was diagnosed with autism as a young child. Years later, Graf ordered genetic testing for the boy and discovered that he had a mutation in the gene SYNGAP1. However, this knowledge didn't change the boy's autism status. "That diagnosis [SYNGAP1] turns out to be very specific for him, but it will never be a household name. Biologically it's good to know, and now it's all over his chart. But on a societal level he still needs this catch-all label [of autism]," Graf says.
"It gives some information, but to what degree does that change treatment or prognosis?"
Jennifer Singh, a sociologist at Georgia Tech who wrote the book Multiple Autisms: Spectrums of Advocacy and Genomic Science, agrees. "I don't know that the knowledge gained from just having a gene that's linked to autism," is that beneficial, she says. "It gives some information, but to what degree does that change treatment or prognosis? Because at the end of the day you have to address the issues that are at hand, whatever they might be."
As more children are diagnosed with autism, knowledge of the underlying genetic mutation causing the condition could help families better understand the diagnosis and anticipate their child's developmental trajectory. However, for the vast majority, an additional label provides little clarity or consolation.
Instead of spending money on genetic screens, Singh thinks the resources would be better used on additional services for people who don't have access to behavioral, speech, or occupational therapy. "Things that are really going to matter for this child in their future," she says.
The federal 'Right to Try' bill in the United States recently passed the House and requires Senate approval before it becomes law. The bill would provide patients access to experimental drugs and other products that have not received approval from the Food and Drug Administration (FDA), including stem cell treatments.
It's not enough to act on a hunch that it might work.
Most folks think this is a good thing, but several express concern over whether the law would truly help patients. Even if a company allows patients to access an experimental drug, an important question remains: Should a doctor prescribe it?
Before such a drug can be prescribed, the federal bill states that a physician must "certify" that the patient has exhausted all available treatments or does not meet the criteria for standard treatment. Even after determining eligibility, a physician needs to consider a few points first. It's not enough to act on a hunch that it might work. The concept of medical innovation could help doctors figure out if prescribing an experimental treatment is the right thing to do.
Medical innovation falls within the doctor's scope of practice. Based on their experience and sound scientific rationale, physicians can "innovate" and offer treatment tailored to a patient with the goal of improving health. This differs from the goal of clinical research, which is to produce generalizable knowledge, not necessarily to benefit patients. In medical specialties like surgery, many of the standard procedures were developed through medical innovation, not clinical trials. Under the 'Right to Try,' a physician could ethically prescribe an experimental therapy as medical innovation if the following conditions are met.
Medical innovation should follow similar ethical and scientific oversight as clinical research.
First, there must be sound scientific rationale, and evidence of safety and efficacy of the innovative treatment from preclinical (animal and lab) research or clinical (human) research. The 'Right to Try' bill permits access to experimental products only after safety is demonstrated from a phase 1 clinical trial. This initial testing, called "first in human," aims to determine safety and dosing of an experimental product on typically around 20 to 100 people who are healthy volunteers or have a condition. This way, a physician can be assured that there is some evidence indicating the product is safe.
Efficacy must be demonstrated in animal and lab preclinical studies in order to gain permission from the FDA to do a phase 1 trial in the first place. This way, a doctor can also be assured that sound scientific rationale exists indicating a potential benefit to the patient. Only through further phase 2 and 3 clinical trials on hundreds or more people would a doctor know with greater certainty that the therapy works, but this might take many more years.
A doctor should not completely rely on what others in the scientific community think about the experimental treatment and should have appropriate expertise. This includes knowledge about the disease, familiarity with treating such patients, and an understanding of how the experimental treatment works, including administering it.
Second, medical innovation should follow similar ethical and scientific oversight as clinical research. Physicians should write a protocol for administering the experimental therapy and have it reviewed by clinical, scientific, and ethics experts at their institution. A protocol would include all the information on how the doctor would provide the therapy to patients, including dosages, monitoring, what happens if there are side effects, and much more. The experts would examine various components of the plan, look at informed consent, and ensure a favorable benefit-to-risk ratio, among other aspects.
When weighing whether to prescribe an experimental treatment, doctors need to base this decision on sound science and relevant clinical experience, not on hope or desperation.
Third, doctors should properly inform their patients about the risks (including if the risks are unknown), possible benefits, and the details of the procedure to be undertaken, and they must obtain the patient's consent.
Fourth, physicians should thoroughly monitor and diligently document all aspects of the outcomes of the procedure, various clinical indicators, and adverse events. During the course of providing an experimental therapy, if harm to a patient occurs, the physician is obligated to alter the course of the treatment or stop it. Similarly, if evidence from an ongoing clinical trial shows that the experimental treatment might help some but not all patients, the doctor needs to modify the plan accordingly.
Fifth, upon completing the experimental treatment, physicians should publish their findings to share the knowledge. Note that medical innovation is not meant to replace clinical trials. The two can be complementary, and medical innovation can lead to the design of clinical trials to demonstrate safety and efficacy.
Other experts may not agree that it can be ethical for a physician to prescribe an unapproved drug. Such dissenters would claim that physicians should only prescribe medications when there is substantial scientific and clinical certainty that a product is safe and effective for patients. They are also likely to oppose most forms of medical innovation. Yet even after undergoing rigorous clinical trials, some approved products have been shown to be unsafe or ineffective and are removed from the market.
While it seems that more evidence is better, doctors need to be mindful that patients are suffering and some may never receive access to drugs still in the pipeline. Bound by the Hippocratic Oath – the main tenet being "do no harm" – doctors are obligated to prescribe therapies that will help their patients. When weighing whether to prescribe an experimental treatment, doctors need to base this decision on sound science and relevant clinical experience, not on hope or desperation. Given that patients who want to participate in the 'Right to Try' movement have exhausted all other options and their condition may be worsening, it would seem ethically appropriate for a physician to treat them with an experimental drug, as long as the criteria listed above are satisfied.
The views expressed are the author's personal views, and do not necessarily reflect the policy or position of Mayo Clinic.
When farmer Terry Wanzek walks out in his fields, he sometimes sees a grove of trees, which reminds him of his grandfather, who planted those trees. Or he looks out over the pond, which deer, ducks and pheasant use for water, and he knows that his grandfather made a decision to drain land and put the pond in that exact spot.
Growing more with fewer resources is becoming increasingly urgent as the Earth's population is expected to hit 9.1 billion by 2050.
"There is a connection that goes beyond running a business and making a profit," says Wanzek, a fourth-generation North Dakota farmer who raises spring wheat, corn, soybeans, barley, dry edible beans and sunflowers. "There is a connection to family, to your ancestors and there is a connection to your posterity and your kids."
Wanzek's corn and soybeans are genetically modified (GM) crops, which means that they have been altered at the DNA level to create desirable traits. This intervention, he says, allows him to start growing earlier and to produce more food per acre.
Growing more with fewer resources is becoming increasingly urgent as the Earth's population is expected to hit 9.1 billion by 2050, with nearly all of the rise coming from developing countries, according to the Food and Agriculture Organization of the United Nations. This population will be urban, which means they'll likely be eating fewer grains and other staple crops, and more vegetables, fruits, meat, dairy, and fish.
Whether those foods will be touched in some way by technology remains a high-stakes question. As for GM foods, the American public is somewhat skeptical: in a recent survey, about one-third of Americans report that they are actively avoiding GMOs or seek out non-GMO labels when shopping and purchasing foods. These consumers fear unsafe food and don't want biotechnologists to tamper with nature. This disconnect—between those who consume food and those who produce it—is only set to intensify as major agricultural companies work to develop further high-tech farming solutions to meet the needs of the growing population.
"I don't think we have a choice going forward. The world isn't getting smaller. We have to come up with a means of using less."
In the future, it may be possible to feed the world. But what if the world doesn't want the food?
A Short History
Genetically modified food is not new. The first such plant (the Flavr Savr tomato) was approved for human consumption and brought to market in 1994, but people didn't like the taste. Today, nine genetically modified food crops are commercially available in the United States (corn, soybean, squash, papaya, alfalfa, sugar beets, canola, potato and apples). Most were modified to increase resistance to disease or pests, or tolerance to a specific herbicide. Such crops have in fact been found to increase yields, with a recent study showing grain yield was up to 24.5 percent higher in genetically engineered corn.
Despite some consumer skepticism, many farmers don't have a problem with GM crops, says Jennie Schmidt, a farmer and registered dietician in Maryland. She says with a laugh that her farm is a "grocery store farm - we grow the ingredients you buy in products at the grocery store." Schmidt's father-in-law, who started the farm, watched the adoption of hybrid corn improve seeds in the 1930s and 1940s.
"It wasn't a difficult leap to see how well these hybrid corn seeds have done over the decades," she says. "So when the GMOs came out, it was a quicker adoption curve, because as farmers they had already been exposed to the first generation and this was just the next step."
Schmidt, for one, is excited about the gene-editing tool CRISPR and other ways biotechnologists can create food like apples or potatoes with a particular enzyme turned off so they don't go brown during oxidation. Other foods in the pipeline include disease-resistant citrus, low-gluten wheat, fungus-resistant bananas, and anti-browning mushrooms.
"We need to not judge our agriculture by yield per acre but nutrition per acre."
"I don't think we have a choice going forward," says Schmidt. "The world isn't getting smaller. We have to come up with a means of using less."
A Different Way Forward?
But others remain convinced that there are better ways to feed the planet. Andrew Kimball, executive director of the Center for Food Safety, a non-profit that promotes organic and sustainable agriculture, says the public has been sold a lie with biotech. "GMO technology is not proven as a food producer," he says. "It's just not being done anywhere at a large scale. Ninety-nine percent of GMOs are corn and soy, and they allow chemical companies to sell more chemicals. But that doesn't increase food or decrease hunger." Instead, Kimball advocates for a pivot from commodity agriculture to farms with crop diversity and animals.
Kimball also suggests a way to use land more appropriately: stop growing so much biofuel. Right now, in the U.S., more than 55 percent of our crop farmland is in corn and soy. About 40 percent of that goes into cars through ethanol, 40 percent is fed to animals and a good bit of the rest goes into high-fructose corn syrup. That leaves only a small amount to feed people, says Kimball. "If you want to feed the world, not just the U.S., you want to make sure to use that land to feed people," he says. "We need to not judge our agriculture by yield per acre but nutrition per acre."
Robert Streiffer, a bioethicist at the University of Wisconsin at Madison, agrees that GMOs haven't really helped alleviate hunger. Glyphosate resistance, one of the traits that is most commonly used in genetically engineered crops, doesn't improve yield or allow crops to be grown in areas where they weren't able to be grown before. "Insect resistance through the insertion of a Bt gene can improve yield, but is mostly used for cotton (which is not a food crop) and corn which goes to feed cattle, a very inefficient method of feeding the hungry, to say the least," he says. Important research is being done in crops such as cassava, which could help relieve global hunger. But in his opinion, these researchers lack the profit potential needed to motivate large private funding sources, so they require more public-sector funding.
"A substantial portion of public opposition is as much about the lack of any perceived benefits for the consumers as it is for outright fear of health or environmental dangers."
"Public opposition to biotech foods is certainly a factor, but I expect this will slowly decline as labels indicating the presence of GE (genetically engineered) ingredients become more common, and as we continue to amass reassuring data on the comparative environmental safety of GE crops," says Streiffer. "A substantial portion of public opposition is as much about the lack of any perceived benefits for the consumers as it is for outright fear of health or environmental dangers."
One sign that the public may be willing to embrace some non-natural foods is the recent interest in cultured meat, which is grown in a lab from animal cells but doesn't require raising or killing animals. A study published last year in PLOS One found that 65 percent of 673 surveyed U.S. individuals would probably or definitely try cultured meat, while only 8.5 percent said they definitely would not. In the future, lab-grown food may become another way to create more food with fewer resources.
Danielle Nierenberg, president of the Food Tank, a nonprofit organization focused on building a global community of safe and healthy food, points to an even more immediate problem: food waste. Globally, about a third of food is thrown out or goes bad before it has a chance to be eaten. She says simply fixing roads and infrastructure in developing countries would go a long way toward ensuring that food reaches the hungry. Focusing on helping small farmers (who grow 70 percent of food around the globe), especially female farmers, would go a long way, she says.
Innovation on the Farm
In addition to good roads, those farmers need fertilizer. Nitrogen-based fertilizers may get a boost in the future from technologies that release nutrients slowly over time, like slow-release medicines based on nanotechnology. In field trials on rice in Sri Lanka, one such nanotech fertilizer increased crop yields by 10 percent, even though it delivered only half the amount of urea compared with traditional fertilizer, according to a study last year.
"I'm not afraid of the food I grow. We live in the same environment, and I feel completely safe."
One startup, the San-Francisco-based Biome Makers, is profiling microbial DNA to give farmers an idea of what their soil needs to better support crops. Joyn Bio, another new startup based in Boston and West Sacramento, is looking to engineer microbes that could reduce farming's reliance on nitrogen fertilizer, which is expensive and harms the environment. (Full disclosure: Joyn Bio and this magazine are funded by the same company, Leaps by Bayer, though leapsmag is editorially independent. Also, Bayer recently acquired Monsanto, the leading producer of genetically engineered seeds and the herbicide Roundup.)
Terry Wanzek, the farmer in North Dakota, says he'd be willing to try any new technology as long as it helps his bottom line – and increases sustainability. "I'm not afraid of the food I grow," he says of his genetically modified produce. "We eat the same food, we live in the same environment, and I feel completely safe."
Only time will tell if people several decades from now feel the same way. But no matter how their food is produced, one thing is certain: those people will need to eat.