The number of genes involved in autism is a mind boggling eight hundred. That's why autism is called autism spectrum disorder - because it is actually a group of neurodevelopmental disorders with a wide range of symptoms.
They're grouped into three diagnoses: Autistic Disorder, Asperger Syndrome, and PDD-NOS, which stand for Pervasive Developmental Delays - Not Otherwise Specified. The diagnosis involves three areas of impairments: abnormal communication, impaired social functions and repetitive behaviors and restricted interests. Autistic disorder is the most severe and includes impairment in all three.
For example, fifty percent of the kids don't speak and repeat behaviors like hand flapping or rocking. People with PDD-NOS have some but not all of the symptoms, and Asperger's kids face social challenges but aren't burdened with communication or cognitive defects.
No two autistic children likely have the same genetic mutations that caused their disorder. Five to ten percent of the kids have new mutations not found in their parents, and men over fifty tend to produce sperm with more new mutations, upping their chance of having an autistic child.
Gene mutations, along with environmental exposures, could cause autism, including gestational diabetes, folic acid deficiency, air pollution, and the type of bacteria in the child's gut. One new theory is that some people with autism have different connections between different brain areas. Scientists are dedicated to discovering just what causes ASD.
One fact is irrefutable, however, and that is that autism is not caused by vaccines!
For more information…
What Causes Autism? What We Know, Don't Know, and Suspect
We're finally getting closer to understanding.
Autism Spectrum Disorder Fact Sheet
From the National Institute of Neurological Disorders and Stroke
Vaccines Don't Cause Autism, Even in Kids at Higher Risk
In the latest study on the vaccines, researchers find even more evidence that childhood immunizations aren't linked to autism.
Vaccines Do Not Cause Autism
From the Centers for Disease Control and Prevention