Trace of autism's origins found in brain

Washington: Researchers have found a major new clue to the origins of autism, pinpointed what types of cells and regions of the developing human brain are affected by gene mutations linked to the disorder.

Analyzing massive amounts of gene expression data generated by the BrainSpan project, the Yale-led team of researchers identified common neural circuits affected by autism-risk genes and when, where, and in what cell types those genes exert their effects on the developing human brain and lead to autism spectrum disorders.

Co-senior author of the paper, Nenad Sestan said although other genes and neural circuits that contribute to autism spectrum still remain to be found, the new findings suggested new-targeted treatments for autism might be possible.

The Yale team was led by Sestan and Matthew State, now at the University of California-San Francisco, together with James Noonan of Yale School of Medicine, Bernie Devlin of the University of Pittsburgh, and Kathryn Roeder of Carnegie-Mellon University. Yale team tackled the difficulty by searching for molecular crossroads shared by nine genes conclusively linked to autism.

An analysis of when and where nine of those autism genes are most co-activated identified at least two such molecular crossroads.

The first influence a specific cell type- excitatory projection neurons- and their neural circuits, which form and become active about three to five months after conception. The second implicates the mid-fetal frontal cortex, a brain region critical for cognition, language, and complex motor behaviours.