North Center for
Diagnosis & Intervention

Special Corner

 

 

What Causes Autism?
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Not long ago, the answer to this question would have been “we have no idea.” Research is now delivering the answers. First and foremost, we now know that there is no one cause of autism just as there is no one type of autism. Over the last five years, scientists have identified a number of rare gene changes, or mutations, associated with autism. A small number of these are sufficient to cause autism by themselves. Most cases of autism, however, appear to be caused by a combination of autism risk genes and environmental factors influencing early brain development. In the presence of a genetic predisposition to autism, a number of nongenetic, or “environmental,” stresses appear to further increase a child’s risk. The clearest evidence of these autism risk factors involves events before and during birth. They include advanced parental age at time of conception (both mom and dad), maternal illness during pregnancy and certain difficulties during birth, particularly those involving periods of oxygen deprivation to the baby’s brain. It is important to keep in mind that these factors, by themselves, do not cause autism. Rather, in combination with genetic risk factors, they appear to modestly increase risk.

 

Are Vaccines to Blame?
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Many studies have been conducted to determine if a link exists between immunization and increased prevalence of autism, with particular attention to the measles-mumps-rubella (MMR) vaccine and vaccines containing the preservative thimerosal. These studies have found no link between vaccines and autism. We strongly encourage parents to have their children vaccinated, because this will protect them against serious diseases. It remains possible that, in rare cases, immunization might trigger the onset of autism symptoms in a child with an underlying medical or genetic condition.

 

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