Many factors may lead to symptoms of autism spectrum disorder (ASD). If a family already has a child diagnosed as having ASD, the chance that a sibling might also have ASD is 10 to 20 times higher than in the general population. Read on to learn more from the American Academy of Pediatrics about the causes of ASD.

Studies have shown that relatives of children with ASD are more likely to have some similar social and behavioral characteristics to those seen among children with ASD but not severe enough to merit a diagnosis. Behavioral symptoms may include social awkwardness, inflexibility, and repetitive behaviors.

ASD may occur more often in children with certain medical conditions or high risk factors. These medical conditions can include fragile X syndrome, tuberous sclerosis complex, Down syndrome, or other genetic disorders. However, most children with ASD do not have these or any other specific genetic conditions....

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