More than 30% of people with autism also have some kind of stomach or intestinal problem, compared with fewer than 10% of people who aren’t autistic, says study author Daniel Campbell, research assistant professor at Vanderbilt University.
That suggests the genetic variation may be responsible for causing autism in this specific group of people, although it may not be related to other cases of autism, Campbell says.
As scientists learn more about the disease, Campbell says, it appears that autism is not a single disease but a spectrum of disorders with common symptoms but different causes.
Campbell’s research was financed by the National Institutes of Health, a private group called Cure Autism Now and other sources.
Some researchers say Campbell’s findings, although intriguing, are preliminary.
Hakon Hakonarson, an autism researcher and director of Children’s Hospital of Philadelphia’s Center for Applied Genomics, says it would be surprising for one gene to be responsible for the wide variety of problems included in the study: chronic constipation, chronic diarrhea, reflux, irritable bowel syndrome and ulcers.
Researchers need to try to replicate their findings in a different group of people to prove that the results were not just the result of chance, says Hakonarson, who was not involved in the study.
Campbell says he’s working on a more definitive study. In his current paper, he relied on parents to describe their children’s gastrointestinal difficulties. In his new project, children will be seen by a gastroenterologist, who will be able to confirm the gastrointestinal problems.