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.