Combining two genome analysis approaches supports immune system contribution to autism

Researchers using novel approaches and methodologies of identifying genes that contribute to the development of autism have found evidence that disturbances in several immune-system-related pathways contribute to development of autism spectrum disorders. The report published December 4 in the open-access journal PLOS ONE powerfully supports a role for the immune function in autism by integrating analysis of autism-associated DNA sequence variations with that of markers identified in studies of families affected by autism.

"Others have talked about immune function contributions to autism, but in our study immune involvement has been identified through a completely nonbiased approach," says Vishal Saxena, PhD, of the Massachusetts General Hospital (MGH) Department of Neurology, first, corresponding and co-senior author of the PLOS ONE paper. “We let the data tell us what was most important; and most tellingly, viral infection pathways were most important in this immune-related mechanism behind autism.”

Genetic studies of families including individuals with autism have indentified linkages with different locations in the genome. Since traditional interpretation methods implicate the gene closest to a marker site as the cause of a condition, those studies appeared to point to different genes affecting different families. However, Saxena’s team realized that, since autism has typical symptoms and affects the same biological processes, a common molecular physiology must be affecting the different families studied. To search for genetic pathways incorporating these autism-associated sites, they developed a methodology called Linkage-ordered Gene Sets (LoGS) that analyzes all of the genes within a particular distance from marker sites and ranks them according to their distance from the marker.