Valerie Clark
Oct 6, 2011

Autism research advances with new mouse study


Establishing a medically based, cause-and-effect link for autism sufferers has been challenging to say the least. The Autism Speaks advocacy group has raised millions of dollars to create awareness about autism spectrum disorders (ASD) and fund research efforts to find answers and cures for core autistic behaviors. The most recent reports estimate that 1.5 million people, at least 1 out of 110 children, in the United States alone suffer from some form of autism. However, a milestone has been reached by a team of scientists from the David Geffen School of Medicine at UCLA. The mouse equivalent to the human CNTNAP2 (contactin associated protein-like 2) gene, also known as Caspr2, has been previously linked to ASD, but for the first time, scientists have developed an in vivo tool for the treatment of ASD-related effects in humans.

The three core behaviors individuals with autism experience are decreased socialization, decreased communication and repetitive behaviors, including epileptic seizures in humans with a Caspr2 genetic mutation. Recent research has shown that Caspr2 plays a functional role in ASD and that the absence of this gene leads to epilepsy, neurological abnormalities and core autism-related behaviors in mice and humans. To be specific, scientists have attributed the ASD-related effects observed in Caspr2-deficient mice to a dysfunctional neural network rather than abnormal neural activity. In other words, this gene is linked not only to ASD but also to early brain development. Without Caspr2, mice displayed three core autistic behaviors in addition to seizures and hyperactivity. 

The problem scientists were dealing with was how to correct the neurologically based developmental deficits observed in Caspr2-deficient specimens. The answer was risperidone, an FDA-approved drug (with the brand name Risperdal). Risperidone is classified as an atypical anti-psychotic drug that affects neurological function. In Caspr2-deficient mice, the neurological effects on nerve firing and synchronization were resolved upon treatment with risperidone. Risperidone treatment did not have an effect on socialization behaviors, which illuminates the distinct circuitries related to the core autistic behaviors. 

Treatment of presumably autistic mice with risperidone for 7 to 10 days propelled researchers closer to understanding the neurological deficiencies in autistic patients. Risperidone is generally prescribed to treat severe mental illnesses in adults, such as schizophrenia and bipolar disorder, but this new research demonstrates an indication for ASD-related neurological effects in juvenile patients who lack the Caspr2 gene. Although risperidone treatment may resolve epileptic incidences, neuronal network function and hyperactivity, it is not a cure; nor do we know the cause of a Caspr2 deficiency. 

Millions of dollars have been raised by advocacy groups like Autism Speaks to foster advancements in autism research and raise awareness about the disorder. With every advancement and problem solved, the future direction for autistic research initiatives unfolds. We may never cure genetic-related disorders like autism, cancer and AIDS, but through innovative research and drug development, we can continue connecting the dots and linking cause and effect.