With the help of two sets of brothers with autism, Johns Hopkins scientists have identified a gene associated with autism that appears to be linked very specifically to the severity of social interaction deficits.
The gene, GRIP1 (glutamate receptor interacting protein 1), is a blueprint for a traffic-directing protein at synapses those specialized contact points between brain cells across which chemical signals flow.
Identified more than a decade ago by Richard L. Huganir, Ph.D., professor and director of the Solomon H. Snyder Department of Neuroscience at the Johns Hopkins University School of Medicine, and a Howard Hughes Medical Institute investigator, GRIP1 regulates how fast receptors travel to a cell's surface, where they are activated by a brain-signaling chemical called glutamate, allowing neurons to communicate with one another.
The new study, which tracked two versions of GRIP1 in the genomes of 480 people with autism, was published March 22 in the Proceedings of the National Academy of Sciences, and lends support to a prevailing theory that autism spectrum disorders (ASD), molecularly speaking, reflect an imbalance between inhibitory and excitatory signaling at synapses.
"The GRIP1 variants we studied are not sufficient to cause autism by themselves, but appear to be contributing factors that can modify the severity of the disease," says Tao Wang, M.D., Ph.D., assistant professor, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine. "GRIP1 mutations seem to contribute to social interaction deficits in the patients we studied."
The Johns Hopkins researchers examined a part of the genomes of 480 patients with autism and compared these with 480 people of similar ethnicity without the disorder. They analyzed about 50 genes known to make proteins involved in a brain-signaling pathway, ultimately focusing their investigation on GRIP1, a protein found at bot
|Contact: Maryalice Yakutchik|
Johns Hopkins Medical Institutions