Research Finds Gene Linking Autism and Gastrointestinal Problems

For years, parents have insisted that there is a link between gastrointestinal issues and autism. Researchers found little evidence, though, of a higher incidence of GI problems among people with autism. Now mounting evidence suggests that there may be a genetic link between GI issues and at least some cases of autism.

In March 2009, a study led by researchers at the University of Southern California (USC) and Vanderbilt University identified a specific gene variant that links increased genetic risk for autism with gastrointestinal conditions. According to a press release from Vanderbilt University:

"It is well known that GI conditions are common among individuals with autism, but not known if co-occurring GI conditions represent a unique autism subgroup.

"Some speculate that GI dysfunction impacts brain development, or that altered nervous system development affects GI function. The MET protein participates in both brain development and GI repair, suggesting that disruption of MET signaling may contribute to both medical conditions.

"...The MET rs1858830 C allele was associated with both autism and GI conditions in 118 families containing at least one child with co-occurring autism and GI conditions. In contrast, there was no association of the MET polymorphism with autism in the 96 families lacking a child with co-occurring autism and GI conditions."

The research findings from this particular study are preliminary, and more research is needed. Nevertheless, it does appear to support both prior research findings and claims by many members of the autism community that there really is a correlation between autism and GI disorders.

On the other hand, though, it tends to undercut some of the theories for WHY such a correlation exists. While many have insisted that the correlation relates to measles virus left in the gut after the MMR vaccine, this study suggests that the correlation is genetic in nature.

This finding is an exciting step forward in what could be a critical issue in autism research: the definition of sub-groups with varying symptoms and etiologies. It's also likely to keep the "what causes autism" debate up to its usual fiery standards.

_Sources:

Campbell, Daniel B. et al. "Distinct Genetic Risk Based on Association of MET in Families With Co-occurring Autism and Gastrointestinal Conditions." Pediatrics, 10.1542/peds.2008-0819.

Sousa I, Clark TG, Toma C, Kobayashi K, Choma M, Holt R, Sykes NH, Lamb JA, Bailey AJ, Battaglia A, Maestrini E, Monaco AP. "MET and autism susceptibility: family and case-control studies." Eur J Hum Genet. 2008 Nov 12.

Vanderbilt University. "MET gene linked to autism, gastro-intestinal problems in children." March 3, 2009.