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What Causes Autism?

The search for what causes autism is ongoing. Scientists and researchers have not been able to pinpoint the specific causes of Autism Spectrum Disorders (ASD) despite numerous theories. Most scientists generally agree that autism results from a series of abnormalities in a child’s brain development and function. Autism causes might also be hereditary, with certain families having a genetic predisposed to ASD. Possible causes of autism also include a variety of environmental conditions, complications at birth, or a combination of the two.

Brain scans have consistently shown that children with autism have a different structure and shape to their brain compared to children without autism. Some cases of autism have shown higher levels of serotonin and other neurotransmitters in the brain. This suggests that these irregularities result from a disruption early on in the fetal brain development process including defects in the way that brain cells communicate with each other. Other theories suggest that the body’s immune system produces a rare form of antibodies that attack portions of the brain in developing children. It is also widely believed that children with autism have an abnormal brain growth rate with their brains growing at an accelerated rate early on and then slowing down when other children’s brains get larger, causing irregularities in brain function and activity.

Many cases have shown that autism causes might be inherited. Certain genetic factors might make children more susceptible to autism. No one gene has been proven to cause autism, but some families seem to have a pattern of autistic behavior and other related neurological disabilities and disorders. Research in possible genetic causes of autism is ongoing. Scientists are eager to pinpoint specific gene irregularities that might lead to autism. Other studies show that a cluster of unstable genes might impair a child’s brain development, causing autism.

To further prove this theory, several cases show that parents with one child with autism are more likely, up to 5 percent or one in 20, to have another child with autism. According to the Center for Disease Control and Prevention (, this is far above the national average, which shows that about 1 in 68 children, roughly 1.47 percent, are diagnosed with autism. Studies with identical twins have shown that if one twin has autism, the other twin has up to a 90 percent chance of having autism. Many children with autism have also had parents or relatives with social and cognitive impairments or tend to engage in repetitive behavior. These studies are ongoing, yet they do strongly support the notion that autism is somehow related to genetics and could possibly be hereditary.

Other researchers continue to explore the idea that environmental issues may play a hand in causing autism. Issues or complications during pregnancy, viral infections, metabolic imbalances, or an exposure to chemicals rank among other leading possible causes of autism. There is little consensus that these theories are valid, but scientists are investigating any and all possibilities. Additionally, studies have shown that autism tends to appear more frequently among individuals with certain medical conditions such as fragile X syndrome, congenital rubella syndrome, and tuberous sclerosis. You can take a look at the full list of related disorders here (

Our understanding of autism is still quite limited. As research continues, new theories and possible causes of autism materialize all the time. You can go to the Autism Research Institute ( for more information on the origins and causes of autism.