There is no known cause of autism. However, it's likely that genetics may be one of the possible causes (although scientists aren't certain). Recent research into possible autism causes strongly suggests that certain people have a genetic predisposition for the disorder. Other possible causes involve abnormal levels of neurotransmitters in the brain.
An Overview of the Causes of AutismScientists aren't certain of the cause of autism, but it's likely that both genetics and environment play a role.
Recent studies strongly suggest that some people have a genetic predisposition to autism. In families with one autistic child, the risk of having a second child with the disorder is approximately 5 percent, or one in 20. This is greater than the risk for the general population.
Researchers are looking for clues about which genes contribute to increased susceptibility. In some cases, parents and other relatives of an autistic child show mild impairments in social and communicative skills or engage in repetitive behaviors. Evidence also suggests that some emotional disorders, such as manic depression, occur more frequently than average in the families of people with autism.
The theory that parental practices are responsible for autism has now been disproved.
Some studies suggest that people with autism have abnormal levels of serotonin or other neurotransmitters in the brain. These abnormalities suggest that autism could result from the disruption of normal brain development early in fetal development caused by defects in genes that control brain growth and that regulate how neurons communicate with each other. While these findings are intriguing, they are preliminary and require further study.