Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain. There is no single known cause of ASD, but research suggests that it develops from a combination of genetic and nongenetic, or environmental, influences. Some of the known risk factors for developing ASD include:
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Genetic factors: Autism tends to run in families, and changes in certain genes increase the risk that a child will develop autism. If a parent carries one or more of these gene changes, they may get passed to a child (even if the parent does not have autism). Other times, these genetic changes arise spontaneously in an early embryo or the sperm and/or egg that combine to create the embryo.
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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.
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Other factors: Other factors that may increase the risk of developing ASD include having a sibling with autism, older parents, certain genetic conditions, such as Down, fragile X, and Rett syndromes, very low birth weight, premature labor and birth, complications during birth, and maternal diabetes or obesity.
Its important to note that while some people with ASD have a known genetic difference, such as a genetic condition, other causes are not yet known.
