Wednesday, October 5, 2011

Genetically Engineering Autistic Mice

Discovering the causes of autism continues to be a notoriously complicated process in the scientific world, as a variety of genetic factors as well as external factors such as childhood vaccines have been implicated as possible causes. It is widely accepted that there is a substantial genetic basis for the disease, but it has been unclear exactly how and to what extent genetic mutations or deletions/duplications manifest themselves in autistic people. Recent studies in which mice have been genetically engineered may bring us closer to understanding the effect of genetic abnormalities on autism and lead us to finding preventative treatments.

Researchers at the Beth Israel Deaconess Medical Center in Boston have manipulated the UBe3a gene in mice on chromosome 15 in the 11-13 segment, a region which has been implicated in causing developmental delays in humans. (Ube3a is one of about 40 genes that fall in this segment.) Abnormalities in this region are widely accepted as being the most common genetic cause of autism, affecting about 3% of people with the disease. The researchers tripled the Ube3a gene in their test mice and then observed their behaviors. Sure enough, the manipulated mice exhibited the three most common characteristics of autistic behavior observed in humans: reduced social interaction, impaired communication, and excessive repetitive behaviors.

Researchers are continuing to research how exactly the alterations to the UBe3a are expressed in terms of neuronal defects in the brain. Further understanding of these defects could in turn lead to treatments or autism that focus on the biological causes of the disease as opposed to the symptoms it produces. It is worth noting, however, that the disease has multiple and potentially interacting causes that make the use of models tricky. Furthermore, as neuroscientist Mary Blue at the Kennedy Krieger Institute noted, clinicians may be skeptical of using mice as models for a disease which hinges so largely on the shortcomings of human communication because "mice can't talk." Nonetheless, this research resonates widely in the field of autism studies.


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