Date Published: October 3, 2024

This is a SPARK Research Summary Report. It describes results from newly published research using data from SPARK participants.

Study title

Return of Genetic Research Results in 21,532 Individuals with Autism

What was the study about?

Researchers analyzed the DNA of 21,532 people with autism and 17,785 of their parents to identify variations that were a cause of the participant’s autism. The study aimed to communicate these results back to participants and to better understand what can be learned by sequencing the DNA of individuals with autism.

How was the research done?

SPARK participants submitted saliva samples for DNA sequencing. Researchers analyzed the results, looking for strong variations in DNA that could lead to autism and intellectual disability. When variations were found, SPARK shared that information with participants, if they wanted to know. Researchers also compared genetic results to information that participants submitted about medical conditions and features that they or their children have.

What did the researchers learn?

• SPARK found genetic variations that cause autism in 1,861 autistic children and adults, almost 9 percent of those who submitted saliva samples. Most variants occurred by chance and were not inherited from parents.¹
• Autistic people with one of the following conditions and features were two to five times more likely to have a genetic cause of autism identified by the study: cognitive delays/impairments, motor delays, short height, unusually small or large head size, seizure disorder, misaligned eyes, difficulty gaining weight, and not being able to control the bowels or bladder at the typical age in childhood.
• Almost a third of the people with three or more of those features had a genetic variant.
• People diagnosed more than 20 years ago had more of those features. They were 50 percent more likely to have a genetic variant than people diagnosed more recently.
• Four percent of people with variants did not have any of those features.
• Autistic girls and women were more likely to have a genetic variant than boys and men (about 12 percent versus 8 percent).
• Researchers found more than 400 changes to different genes or parts of chromosomes in autistic people. More than 40 percent of these variations affected only one person.

What was new and innovative about the study?

The study is the most extensive examination so far of what people can learn about their autism from their DNA. Also, by analyzing the DNA of everyone who provides a sample, regardless of their support needs or other medical conditions, SPARK is creating a fuller picture of how variations may affect autistic people.

What do the findings mean?

Just as autism affects people differently, the variations in DNA that contribute to autism also differ widely. Yet people who have some similar conditions, such as cognitive impairment or motor delays, are more likely to have the strong genetic variants identified in the study, than people who don’t.

What are people saying?

Study Participant:

“We knew we wanted to be part of an autism study, but we didn’t know if we’d learn anything, and we waited two years for an answer. When we did get our answer, we were surprised and excited because then we knew what our next steps to help our son could be. And to me, this is a way for him to help people that are like him.”

Study Researchers:

Wendy Chung, M.D., Ph.D., chief of pediatrics, Boston Children’s Hospital, and lead researcher for SPARK: “We hope people with autism and their families can use this information to understand more about themselves and unlock their full potential.”

Jessica Wright, Ph.D., SPARK scientist and lead author: “It’s hard to express just how meaningful hearing about these genetic changes can be for people who have wondered about themselves, or their family members, for years, even if it doesn’t immediately change how they approach their medical care. For autistic people, it can be another step toward understanding themselves. For families, it can release nagging feelings of misplaced guilt, or feel like the end of a massive diagnostic odyssey.”

What’s next?

Researchers are still finding new genetic variations that could cause autism. As the number of variations grow, SPARK will reanalyze participants’ DNA to see if they have one of the newly discovered variations.

References

1. Wright J.R. et al. Genet. Med. Epub ahead of print (2024) PubMed