When Autism Has no Known Cause
Written or medically reviewed by a board-certified physician. See About.com's Medical Review Policy.
Updated July 24, 2015.
Approximately 85% of autism is "idiopathic." What exactly does that mean - and how does it relate to your situation?
Answer: When autism is of known origin (caused by a known genetic anomaly or exposure), it is referred to as "secondary autism." When autism is of unknown origin, it is called "idiopathic autism."
In about 15% of cases, doctors can pinpoint the cause of autism. But while there are over a dozen established causes of autism, most are very rare genetic disorders or prenatal exposures.
As a result, 85% of people with autism have what is called "idiopathic autism," or autism "of unknown cause." The remaining 15% have "secondary" autism - autism caused by a primary disorder or exposure.
If you have a child with autism - or are an adult on the autism spectrum - chances are you don't know, and won't know, which precise factors caused the disorder.
More About Causes of Autism:
Sources
National Human Genome Research Institute. "Learning About Autism." December 8, 2010.
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