Autism Risk Gene Found to Alter Brain Wiring

MET, a leading candidate gene for autism risk, influences the strength of connections between brain regions involved in social behaviors, and this effect is especially prominent in people with the disorder. The findings are from a large study using several imaging techniques, published 6 September in Neuron.MET is expressed in several areas of the human brain that are active during social tasks. Several studies have shown that common variants in MET appear more frequently in people with autism than in controls, and the link seems to be strongest in people with autism who have gastrointestinal problems. What’s more, MET’s expression is altered in the brains of people with autism, according to postmortem studies.The new report finds that children carrying a common, autism-linked variant in MET have weaker connections — as measured in both activity patterns and anatomy — between distant brain regions. This broadly agrees with a popular hypothesis that autism results from weak long-range connections in the brain, although that theory has lately been called into question.The differences in connectivity appear in children with and without autism, but are more prominent in those with the disorder, the study found. Still, the data also indicate that MET is not the sole or even a primary factor in autism, as many study participants with the disorder don’t carry the variant.“It highlights how all of these genetic factors are contributing to the disorder but they’re not necessarily leading to the disorder,” says lead investigator Mirella Dapretto, professor of psychiatry and biobehavioral sciences at the University of California, Los Angeles.Read more at...SFARI, September 2012.