What causes autism?
Autism spectrum disorder has no single known cause. Given the complexity of the disorder, both genetics and environment may play a role.
Genetics
Several different genes appear to be involved in autism or Autism Spectrum Disorder (ASD).
• ASD can be associated with a genetic disorder, such as Rett syndrome or Fragile X Syndrome.
• Genetic changes (mutations) may increase the risk of autism spectrum disorder.
• Other genes may affect brain development, the way that brain cells communicate, and may determine the severity of symptoms. Some are inherited, while others occur spontaneously.
Environmental Factors
Researchers are exploring whether factors such as viral infections, medications, complications during pregnancy, or air pollutants play a role in triggering autism spectrum disorder.
There is no link between vaccines and autism spectrum disorder. Despite extensive research, no reliable study has shown a link between autism spectrum disorder and any vaccines.
Risk Factors
ASD affects children of all races and nationalities, but certain factors increase a child's risk. These may include:
• Your child's sex. Boys are about 4x more likely to develop ASD than girls but research is ongoing.
• Family history. Families with one child with ASD have a greater risk of having another child with the disorder.
• Other disorders. Certain medical conditions like Fragile X Syndrome, tuberous sclerosis, and Rett syndrome have a higher risk of ASD or autism-like symptoms.
• Extremely preterm babies. Babies born before 26 weeks may have greater ASD risk.
• Parents' ages. There may be a connection between children born to older parents and ASD, but more research is necessary to confirm this.
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