The Centers for Disease Control and Prevention estimated that if 4 million children are born each year in the United States, about 36,500 of them will be diagnosed with an autism spectrum disorder. Autism spectrum disorders, also called pervasive developmental disorders, can range from mild to severe and include autism, Asperger's syndrome, childhood disintegrative disorder, Rett syndrome and pervasive developmental disorder not otherwise specified. With an estimated one in every 110 children diagnosed with an autism spectrum disorder, Autism Speaks noted that it makes autism more common that pediatric AIDS, juvenile diabetes and childhood cancer combined.
While the symptoms vary depending on the type of autism spectrum disorder, a common symptom is an impairment of social skills. For example, a child may not respond to her name or does not understand social cues, according to the National Institute of Neurological Disorders and Stroke.
While the exact cause of autism is not yet known, research has looked at abnormalities in the brain. The National Institute of Mental Health noted that studies using MRIs and post-mortem brain tissue have found a connection between autism and certain areas of the brain, including the brain stem, cerebellum, basal ganglia, cerebral cortex, corpus callosum and the limbic system.
In a new study published in Nature, researchers found molecular similarities in the brains of patients with autism. The research took place in three locations – London, Toronto and Los Angeles – and included post-mortem brain tissue from 19 autism patients and 17 controls.
The researchers looked at two lobes in the brain: the frontal lobe and the temporal lobe (this image from MedlinePlus shows the locations of the different lobes of the brain.) In the brain tissue samples from people without autism, the researchers found noticeable differences – for example, they found 500-plus genes that were expressed at different levels, according to Jenifer Goodwin of HealthDay. But when the researchers looked at those two regions in the brain tissue samples from the autism patients, they did not find those same differences – instead, they found eight gene expression differences in the temporal and frontal lobes. This is the first study in autism that looked at gene expression differences in different brain lobes, which may help find new medications for the disorders.
References
Centers for Disease Control and Prevention. Data and Statistics, Autism Spectrum Disorders (ASDs). 2010. Web. 20 June 2011
http://www.cdc.gov/ncbddd/autism/data.html
National Institute of Mental Health. Autism Spectrum Disorders (Pervasive Developmental Disorders). National Institutes of Health, 2010. Web. 20 June 2011
http://www.nimh.nih.gov/health/publications/autism/complete-index.shtml
Autism Speaks. What is Autism?. 2011. Web. 20 June 2011
http://www.autismspeaks.org/what-autism
National Institute of Neurological Disorders and Stroke. Autism Fact Sheet. National Institutes of Health, 2011. Web. 20 June 2011
http://www.ninds.nih.gov/disorders/autism/detail_autism.htm
Goodwin, Jenifer. Scientists Find Molecular Similarities in Brains of Those With Autism. HealthDay, 25 May 2011. Web. 20 June 2011
http://consumer.healthday.com/Article.asp?AID=653278
Reviewed on June 21, 2011
Edited by Alison Stanton