SHREVEPORT, La. — Research suggests that autism spectrum disorder (ASD) develops from a combination of genetic and environmental influences, including social determinants. These factors appear to increase the risk of autism and shape how the condition develops in a child.
Experts note that increased risk is not the same as a direct cause. For example, some gene changes associated with autism are also found in people who do not have the disorder. Similarly, most people exposed to environmental risk factors will not develop ASD. These influences appear to affect crucial aspects of early brain development, specifically how neurons and entire brain regions communicate with each other.
Decades of scientific research have confirmed there is no connection between vaccines and autism. While autism is often diagnosed around the same time children receive routine vaccinations, vaccines play a crucial role in protecting children from serious diseases.
Studies show that autism tends to run in families, with twin studies suggesting that 60 percent to 90 percent of the risk comes from the genome. If a parent carries certain gene changes, they may be passed to a child even if the parent is not autistic. For some, a high risk is associated with a monogenetic disorder like fragile X syndrome, but in most cases, multiple changes in DNA work together with environmental factors. Medical professionals recommend genetic testing to help reveal specific causes or linked conditions like epilepsy, which can lead to more personalized interventions.
According to the National Institute of Environmental Health Sciences, certain environmental influences associated with increased risk include:
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Advanced parental age
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Prenatal exposure to air pollution or certain pesticides
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Maternal obesity, diabetes, or immune system disorders
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Extreme prematurity or very low birth weight
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Birth complications involving oxygen deprivation
Autism prevalence has risen due to increased awareness, broader diagnostic criteria, and improved screening tools. The transition to DSM-5 guidelines broadened the definition of autism to include people with lower support needs who were previously overlooked. Additionally, the widespread use of tools like the Modified Checklist for Autism in Toddlers (M-CHAT) and the American Academy of Pediatrics’ 2007 recommendation for standardized screening at 18- and 24-month visits have led to earlier detection.