There is no known single cause for Autism, but it is generally accepted that it is caused by differences in brain structure or function. Brain scans show differences in the shape and structure of the brain in people with Autism compared to in neurotypical development. Researchers do not know the exact cause of Autism but are investigating a number of theories, including the links among heredity, genetics, and medical problems. There has been misinformation about the cause of Autism. It is not caused by vaccines or due to parenting style or nutrition.
In many families, there appears to be a pattern of Autism or related disabilities, further supporting the theory that the disorder has a genetic basis.
While no one gene has been identified as causing Autism, researchers are searching for irregular segments of genetic code that people with Autism may have inherited. It also appears that some people are born with a susceptibility to Autism, but researchers have not yet identified a single “trigger” that causes Autism to develop.
Other researchers are investigating the possibility that under certain conditions, a cluster of unstable genes may affect brain development in an unexpected way, resulting in Autism. Still other researchers are investigating complications during pregnancy or delivery as well as environmental factors such as viral infections, metabolic imbalances, and exposure to chemicals.