Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain, and it can look different for each child. There is no single known cause of ASD, and given the complexity of the disorder, there are probably many causes. Both genetics and environment may play a role. Here are some of the main causes of autism that have been identified by researchers:

• Genetics: Several different genes appear to be involved in autism spectrum disorder. Research tells us that autism tends to run in families, and changes in certain genes increase the risk that a child will develop autism. However, most gene changes associated with autism can also be found in people who don’t have the disorder, and the majority of these gene changes do not cause autism by themselves.

• Environmental factors: Certain environmental influences may further increase – or reduce – autism risk in people who are genetically predisposed to the disorder. For example, a woman’s exposure to harmful contaminants during pregnancy may trigger a genetic mutation leading to autism in her child. Problems with a mother’s immune system, certain metabolic conditions, or inflammation during pregnancy may also be linked with higher autism risk for her children. However, the increase or decrease in risk appears to be small for any one of these risk factors.

• Unknown factors: Other causes of autism are not yet known. Scientists believe there are multiple causes of ASD that act together to change the most common ways people develop.

Its important to note that vaccines do not cause autism. Early intervention services can greatly improve a child’s development, so its important to receive services as soon as possible if youre concerned about your child.