Researchers identify gene variant associated with autism, GI dysfunction

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Researchers identify gene variant associated with autism, GI

dysfunction

WASHINGTON (Xinhua): 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 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 in different

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.