June 13, 2011

Keys to Unlocking Autism

(Ivanhoe Newswire) -- Yale researchers have discovered that hundreds of small genetic variations are associated with autism spectrum disorders. This new research supports the theory that autism is not caused by one or two major genetic defects but rather by many small variations.

Investigators looked at more than 1,000 families that had a single child with autism, an unaffected sibling and unaffected parents. They compared individuals with autism to their siblings to determine the genetic changes that distinguished the affected child from the unaffected child.

 The researchers say an interesting finding points to the same small section of the genome that causes Williams syndrome. Williams syndrome is a developmental disorder marked by high sociability and an unusual musical talent. The researchers found in autism, there is an increase in the chromosomal material (an extra copy of this region), and in Williams syndrome, there's a loss of that same material.

"What makes this observation particularly interesting is that Williams syndrome is known for a personality type that is highly empathetic, social, and sensitive to the emotional state of others. Individuals with autism often have difficulties in the opposite direction. This suggests that there is an important key in that region to understanding the nature of the social brain," Matthew State, M.D., Ph.D., who is co-director of the Yale Program on Neurogenetics, was quoted as saying.

The researchers also found about 30 other regions in the genome that likely contribute to autism. They have focused on about six of the regions that showed the strongest evidence and are now moving on to a second phase of the study where they are looking at an additional 1,600 families. They hope to identify multiple new regions that are strongly implicated in autism.

SOURCE: Neuron, June, 2011