U.S. researchers identify gene variant associated with autism, gastrointestinal dysfunction

WASHINGTON, March 2 (Chinese media) -- A specific gene variant that links

increased genetic risk for autism with gastrointestinal (GI) conditions has been

identified, according to a study led by researchers at the University of

Southern California (USC) and Vanderbilt University.

The findings suggested that disrupted signaling of a specific gene variant

-- the MET gene, which plays an important role in development and repair of the

GI system, may contribute to a syndrome that includes autism and co-occurring GI

dysfunction, said principal investigator Pat Levitt, director of the Zilkha

Neurogenetic Institute at the Keck School of Medicine of USC and chair-designate

of the department of cell and neurobiology.

The study will appear in the March issue of the journal Pediatrics and is

now available online.

Autism is a developmental disorder characterized by deficits in

communication abilities, social behavior disruption and inflexible behavior;

while GI conditions are common among individuals with autism, and researchers

have long debated whether co-occurring GI dysfunction represents a unique autism

subgroup, Levitt and lead author Daniel Campbell said.

"Gastrointestinal disorders don't cause autism. Autism is a disorder of

brain development," Levitt said, adding that "however, our study is the first to

bring together genetic risk for autism and co-occurring GI disorders in a way

that provides a biologically plausible explanation for why they are seen

together so often."

In the brain, the MET gene is expressed in developing circuits that are

involved in social behavior and communication. Disturbances in MET expression

result in alterations in how these critical circuits develop and mature, said

Levitt.

Researchers analyzed medical history records from 214 families in the

Autism Genetic Resource Exchange (AGRE), and found that a variant in the MET

gene was associated with autism specifically in those families where an

individual had co-occurring autism and a GI condition.

The study brought researchers closer to understanding the complex genetic

risks for autism. However, further research is needed, as different combinations

of genes are likely to result indifferent types of autism features, the director

said.

"We believe that there are other genes that will help identify different

subgroups of individuals who have autism spectrum disorder," Levitt said.

"We also believe that there needs to be research looking at whether the

children with co-occurring GI dysfunction and autism have unique features that

will help us predict what treatments will be best for them," he added.