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Post falsely suggests genes don’t contribute to autism

May 18, 2022 GMT

CLAIM: Kids who have autism don’t have parents, grandparents or great-grandparents who had autism, so the disorder must not be genetic.

AP’S ASSESSMENT: False. While scientists have not pinpointed one single cause for autism, research shows many genes have been associated with autism spectrum disorder and can make it more likely to occur. Genetic and environmental factors both contribute to whether a person will have the disorder, experts say.

THE FACTS: A social media post circulating online this week falsely suggests there is no genetic basis to autism.

“So they tell us Autism is genetic but autistic kids don’t have autistic parents or grandparents or great grandparents or great great grandparents or great great great grandparents,” read the widely shared Facebook post. “You get the message.”

Experts say the post does not accurately portray the way in which genetic factors influence the probability that someone will have autism. Research suggests the disorder is not passed down in a single gene, but can depend on a variety of genes.

“The post is incorrect, as is the assertion that there is not a genetic basis to autism,” said Charles Nelson, a professor of pediatrics and neuroscience at Harvard Medical School. “Autism is undoubtedly a multigenic disorder, involving many genes, mostly acting in concert with one another. Thus, there isn’t a direct, linear association between genes and autism … but that doesn’t mean there isn’t a genetic basis to autism or that the disorder isn’t heritable.”

Dozens of genes have been identified as associated with autism, Nelson said. In many behavioral disorders, genes don’t directly cause the disorder but instead, in combination with each other, make it more likely to occur. The way genes are expressed can be influenced by other genes or by environmental factors.

“It’s kind of an additive effect,” said Dr. Dan Geschwind, a professor of neurology, psychiatry and genetics at the University of California, Los Angeles. Though two parents may not have autism, he said, they can pass down sufficient risk factors that increase the risk of the child getting the disorder.

Spontaneous gene mutations can also result in an individual being predisposed to autism, “so that is genetic but not inherited,” Geschwind said.

Though there are many suspected environmental risk factors for autism, including being born to older parents or having a low birth weight, multiple studies have determined that vaccines do not cause autism.

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This is part of AP’s effort to address widely shared misinformation, including work with outside companies and organizations to add factual context to misleading content that is circulating online. Learn more about fact-checking at AP.