A hallmark symptom of autism spectrum disorders is impairment in social interactions, yet little is known about the neural mechanisms underlying this deficit. In contrast to autism, Williams-Beuren syndrome involves enhanced sociability. The syndrome affects many systems, including the motor, sensory, language, cognitive, emotional and social systems. It is caused by a chromosomal microdeletion. Most individuals with the disorder have relatively preserved language skills in conjunction with high sociability, which are quite opposite from the salient features of autism.
Studies of people with the syndrome and mice that carry the microdeletion strongly suggest that deletion of the GTF2I gene may play a key role in the hyper-sociability. GTF2I controls the expression of many genes in the brain.
Guoping Feng and his colleagues at the Massachusetts Institute of Technology, with their collaborator Dashzeveg Bayarsaihan at the University of Connecticut Health Center, propose to use mice lacking GTF2I to determine the brain regions and neural circuits responsible for the hyper-sociability.
Previous studies have shown that deletion of the SHANK3 gene in mice leads to social interaction deficits. SHANK3 encodes a protein critical for neuron-neuron communication, and deletions or mutations in the gene are strongly linked to autism. The researchers plan to test whether the alterations in social interaction seen in Williams syndrome and autism are caused by different changes in the same neural circuit. Together, these studies may lead to a better understanding of the mechanisms underlying social deficits in both disorders.