According to a study in Monday's Pediatrics researchers have identified a gene variant that is associated with both autism and gastrointestinal disorders in people with autism.

Study author Dr. Daniel B. Campbell, research assistant professor of pharmacology at Vanderbilt University, in Nashville said more than 30 % of people with autism also have some kind of stomach or intestinal disorder as compared to 10% of people without autism. He said the finding may represent early identification of a sub-type of autism.

"This association was not present in another group who have autism and don't have gastrointestinal problems," said Campbell. "We think we're subdividing types of autism in a way that's finally useful."

Campbell and his team focused 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.

"It's involved in how well it repairs itself, how well it responds to insults, taking in foods that upset the stomach," Campbell explained. "We wondered if this MET gene variant that we'd identified two years ago might be involved specifically in a subset of these patients who have both autism and a GI problem."

The researchers examined the medical histories and genetic profiles of 918 individuals from 214 families with autism. They noted that the MET C allele was linked with autism spectrum disorder and GI problems in 118 families who had at least one child with both conditions. In the remaining 96 families who did not have a child with both autism and GI conditions, no such link was found.

This the researchers said could suggest that 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 said as scientists learn more about autism, it seems that it is not a single disease but a spectrum of disorders with common symptoms but different causes.

Summing up Campbell said, "It's important for the public to know that GI problems are present in autism. And in this particular set of individuals who have problems with communication, it's not always that obvious that they have GI problems. Often they can't say, 'My tummy hurts.' They have to find other ways to express that, and it's not always productive."

Hakon Hakonarson, an autism researcher and director of Children's Hospital of Philadelphia's Center for Applied Genomics who was not involved in the study said it seemed surprising that one gene could result in such a variety of problems as the study had indicated and said researchers needed to replicate their findings in a different group to be sure that the results were not a chance happening.

Campbell's research was financed by the National Institutes of Health, a private group called Cure Autism Now and other sources.