Wednesday, March 23, 2011
By causing the mutation of one specific gene, researchers have produced mice with two frequently encountered behavioral traits of persons diagnosed with autism. Autism commonly affects the ability to interact socially and is associated with repetitive behavior. The finding was reported in the March 20 online edition of Nature.
Using mice, researchers at the Massachusetts Institute of Technology (MIT) and Duke University mutated one of the genes associated with autism, known as shank3, a gene that controls the production of the shank3 protein present in the brain. Mice that were given this mutation exhibited repetitive behavior and avoided social interactions with the mice around them.
According to MIT Professor Guoping Feng: “Our study demonstrated that Shank3 mutation in mice lead to defects in neuron-neuron communications.”
Shank3 protein are found in synapses within the brain. Synapses allow brain cells (called neurons) to communicate with each other. The mutation in the mouse gene interfered with this communication, apparently producing the subsequent autism-like traits. Researchers believe their work demonstrates the important role of shank3 in the functioning of brain circuits that determine behavior.
While hundreds of genes have been linked to autism in human patients, only a small percentage have been linked to shank3. Professor Feng hypothesizes that disruptions of other genes that act on the production of brain proteins affecting synaptic communication may also be related to autistic behavior. If this disruption is real, Feng claims that treatments could be developed to correct synaptic function for any defective synaptic protein in an autistic patient.
Feng continued; “These findings and the mouse model now allow us to figure out the precise neural circuit defects responsible for these abnormal behaviours, which could lead to novel strategies and targets for developing treatment.”
About one in 110 children in the U.S., and at least one in 100 in UK, have been diagnosed with an autism spectrum disorder, for which there is currently no effective cure.