Medpedia

Autism is the most common condition in a group of developmental disorders known as the autism spectrum disorders (ASDs). Autistic children have difficulties with social interaction and verbal and nonverbal communication, and exhibit repetitive behaviors or narrow, obsessive interests. Autism varies widely in its severity, with symptoms ranging from mild to severe. In some cases the disorder may go unrecognized. Scientists aren’t certain what causes autism, but it’s likely that both genetics and environment play a role.

There is no single known cause of autism. Contributing causes may include:

• Genetics: There is convincing evidence that autism is a heritable disorder. The identity and number of genes involved remain unknown. 
• Environmental: Epidemiologic studies indicate that environmental factors such as toxic exposures, teratogens, perinatal insults, and prenatal infections such as rubella and cytomegalovirus account for few cases. 
• Toxic exposure: Studies done to date fail to find evidence that immunizations with the measles-mumps-rubella vaccine are responsible for the surge in autism. There has been considerable controversy about a possible toxic or heavy metal (especially mercury) component to autism.