In July of 2017, Lynn Vigo got the answer she had given up on long ago. Eighteen years after her daughter was first diagnosed with autism, she learned that Carrie has a genetic change in a gene called CHD8. The gene, first linked to autism in 2012, is now considered one of the most common risk factors for autism.
Carrie, who turned 21 in November of 2017, is among the first SPARK participants to get a genetic result. “It was a very surreal experience,” says Vigo. “The first thing that came to mind was, after 18 years, I know what caused her autism.”
Vigo says she and her family are still processing the news. But her perception of Carrie’s condition has already begun to shift. “I am seeing Carrie and autism through a different lens,” Vigo says. “I started thinking of her as having CHD8-related syndrome, and the primary feature of that is autism.”
Carrie, who loves long car rides and eating out with her classmates, lives in her own apartment with 24-hour care and support. She was diagnosed with autism in the 1990s, long before families were offered genetic testing for developmental conditions.
The new genetic diagnosis probably won’t change Carrie’s healthcare in the near term. Her providers said they don’t yet know enough about CHD8 to use it to guide therapy. But it does help explain some of the symptoms, including serious gastrointestinal and sleep issues, that have plagued Carrie since birth. Preliminary research shows that other children with changes in the CHD8 gene share these problems.
“Back then, doctors were not aware or convinced that those were key features in kids with autism,” Vigo says. “Sometimes they didn’t believe parents. I think there just wasn’t enough information.” At the time, doctors suggested that Carrie wasn’t getting enough liquid or fiber. The family spent years trying dietary changes and supplements, which had little benefit.
Vigo says knowing the genetic diagnosis 18 years ago might have taken away some of the stress of the situation. “Like most moms, I have always wondered if I did or didn’t do something to cause or contribute to her autism, such as eating or not eating something,” Vigo says. “Knowing it was a spontaneous genetic event at the time of conception made it concrete for me that I had no control over that.”
Fortunately, Carrie’s sleep and gastrointestinal issues have improved as a young adult, a pattern that might be of interest to families with younger children with CHD8 changes. “I think it’s a combination of trial and error and her own maturation,” Vigo says.
Vigo says it was also helpful to learn that Carrie’s genetic change is de novo, meaning it occurred spontaneously rather than being inherited from a parent. “That was a huge relief for my son: he is not a carrier,” she says.
Going forward, Vigo hopes that researchers will study the effectiveness of specific therapies, such as applied behavior analysis and medications, in this subset of children. “I hope there may be a more tailored way of looking at and treating some of these unique characteristics,” Vigo says.
GETTING TO KNOW CHD8
Vigo has a close connection to SPARK. She used to work as a clinical social worker and mental health therapist at Seattle Children’s Autism Center, one of SPARK’s clinical sites. She worked with Raphael Bernier, the center’s clinical director. Vigo says she decided to join SPARK partly because of its large size and partly because it required saliva rather than a blood sample.
After learning of Carrie’s genetic result, Vigo enrolled in one of the University of Washington’s autism studies, the TIGER study. The project, led by Bernier, aims to better characterize people with different autism-linked genetic variations. Carrie and her parents will undergo a battery of tests designed to detect common characteristics among genetic subgroups. “That’s a whole different way of looking at autism,” Vigo says.
The assessment will be much more nuanced than Carrie’s original diagnosis, which was based on clinical observation by a developmental pediatrician. “There was no doubt she had autism. But that was it; there was nothing more specific,” Vigo says. “Now we are looking at it with a more focused field of vision. What do these kids have in common? Where are they different?”
To date, Bernier has studied nearly 30 families with changes in a member’s CHD8 gene. They share a number of features, including large heads, specific facial features, sleep and GI problems, and clear-cut autism.
Carrie fits the pattern. Indeed, Vigo recalls seeing photographs of children diagnosed with a CHD8 change several years ago, long before Carrie’s genetic diagnosis, during one of Bernier’s presentations. “I was sitting next to my colleague and I said, that looks like Carrie,” Vigo says. At the time, she didn’t make anything of it.
In addition to enrolling in TIGER, Vigo joined a Facebook group for CHD8 families. She hopes to become more involved in the group over time, perhaps developing a survey asking parents about their children’s symptoms and the different treatments they’ve tried.
“For parents of older kids who never had genetic testing or who thought there was nothing new to learn, this is a good lesson that this isn’t necessarily true,” Vigo says. “Even at almost 21, there potentially are things you can learn about your child.”
Though Carrie’s genetic results have been a revelation, Vigo says the biggest turning point in her family’s autism journey was not linked to genetics. Instead, it was a subtler shift in perspective that unfolded over Carrie’s childhood.
When Carrie was initially diagnosed with autism, Vigo says the family focused on trying to cure her. But then they began to realize that autism wasn’t going away. “It became clear that she was going to have autism and intellectual disability her whole life and would need significant support throughout her life,” Vigo says. “We didn’t stop therapy or special education, but we stopped trying to fix her. We stopped trying to get autism to go away.”
The family relinquished academic goals and focused on community and self-help skills, like getting dressed. And they embraced some of her unusual behaviors. “Her aloofness, her quirky behavior, her mannerisms, became part of her identity,” Vigo says. “They are endearing and mystifying. It’s a different way of looking at autism and looking at her.”
That shift helped the family surrender to the unknowns of the future and focus on building strengths rather than fretting over deficits. “I think for all of us, it’s a relief,” Vigo says. “I think we all enjoy each other more.”
“For us everything has changed and nothing has changed,” Vigo says. “We love her and want her to be happy and healthy and as independent as she can be.”