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.
Podcast: The Friday Five weekly roundup in health research
The Friday Five covers five stories in research that you may have missed this week. 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.
Here are the promising studies covered in this week's Friday Five:
- Using graphene to repair shoulders
- Testing for PTSD with saliva
- Cancer detection with a microchip
- Best posture for pill taking
- Resilient food for climate change
And an honorable mention goes to research on a new way to induce healthy fat.
Podcast: The Science of Recharging Your Energy with Sara Mednick
If you’re like me, you may have a case of email apnea, where you stop taking restful breaths when you open a work email. Or maybe you’re in the habit of shining blue light into your eyes long after sunset through your phone. Many of us are doing all kinds of things throughout the day that put us in a constant state of fight or flight arousal, with long-term impacts on health, productivity and happiness.
My guest for today’s episode is Sara Mednick, author of The Power of the Downstate, a book about the science of relaxation – why it’s so important, the best ways to go about getting more of it, and the time of day when our bodies are biologically suited to enjoy it the most. As a cognitive neuroscientist at the University of California, Irvine, Mednick has a great scientific background on this topic. After getting her PhD at Harvard, she filled her sleep lab with 7 bedrooms, and this is where she is federally funded to study people sleeping around the clock, with her research published in top journals such as Nature Neuroscience. She received the Office Naval Research Young Investigator Award in 2015, and her previous book, Take a Nap! Change Your Life was based on her groundbreaking research on the benefits of napping.
In our conversation, we talk about how work and society make it tough to get stimulation like food and exercise in ways that support our circadian rhythms, and there just as many obstacles to getting sleep and restoration like our ancestors enjoyed for 99 percent of human history. Sara shares some fascinating ways to get around these challenges, as well as her insights about the importance of exposure to daylight and nature vs nurture when it comes to whether you’re a night owl or an early bird. And we talk about how things could change with work and lifestyles to make it easier to live in accordance with our biological rhythms.
Show notes
3:10 – The definition of “upstates” and “downstates”
5:50 – The power of 6 slow, deep breaths per minute to balance the nervous system
9:05 – Watching out for mouth breathing and email apnea
13:30 – Different ways of breathing for different goals
16:35 – Body rhythms – what is heart rate variability and why is it so important?
21:05 – Are you naturally a morning or night person? Nature vs nurture
27:10 – The perfect storm that gets in the way of following our circadian rhythms
29:15 – The evolution of our pre-bedtime downstates – why it's important to check in with your cave mates
30:10 – The culture shift needed for more people to follow their circadian rhythms and improve their health
35:10 – Employers and communities can build downstates into daily work and life
38:15 – Choosing how we react to the world
41:00 – Being smarter about peak performance
45:09 – The science of pacing yourself for long-term productivity
49:42 – The science of light exposure for circadian rhythms
52:20 – Where to learn more about Sara Mednick’s research and writing
Links:
Sara Mednick’s website https://www.saramednick.com/ and her Twitter
Mednick’s recent book - The Power of the Downstate
Mednick’s book on the benefits of napping - Take a Nap! Change Your Life
The blue light blocking glasses recommended in Mednick’s book https://www.amazon.com/dp/B019C3O2UE?psc=1&ref=ppx_yo2ov_dt_b_product_details
An app for measuring heart rate variability - Elite HRV app https://elitehrv.com/
Thorne take-home Melatonin test