Gene may link autism, digestive problems

From USA Today:

Researchers are studying a gene that may cause both autism and gastrointestinal disorders, a study in March 2's Pediatrics reports.

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.

Campbell is focusing on a gene called MET, which is involved in brain development before birth and in connections between brain cells after birth, as well as in the process through which the gastrointestinal system repairs itself. In his study, a variation in this gene was associated with both autism and gastrointestinal problems in 118 of 214 families. But researchers found no link to the genetic variation in autistic patients who didn't have gastrointestinal problems.

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.