“We hear so much about autism risk factors during pregnancy and delivery. But our kids aren’t born with autism, they develop it later. I don’t get it.”
Today’s “Got Questions?” answer is by developmental-behavioral pediatrician Paul Wang, Autism Speaks senior vice president for medical research.
“When does autism start?” is one of the most profound questions we face in our field. At present, autism can’t be reliably diagnosed until around 2 years of age. However, parents often notice symptoms before then. In fact, analysis of videotapes from children’s first-birthday parties shows that signs of autism are already present for many children at that age, even when parents don’t become concerned until months or years later.
Is it possible that autism starts even earlier? Research tells us “yes.”
In most medical conditions, the underlying processes are triggered before their signs and symptoms become obvious. Consider arthritis. The joints are breaking down and inflammation is setting in years before the aches and pains appear. In dyslexia (reading disability), the symptoms aren’t obvious until a child starts learning how to read. But the symptoms are rooted in brain differences that are present much earlier in development.
A similar chain of events occurs in autism. We know that toxic exposures during pregnancy and complications associated with delivery can disrupt brain processes before birth and shortly afterwards. Mutations in the genes associated with autism can affect how the brain develops and functions, starting well before birth.
Even though the outward symptoms of autism may not be apparent immediately after birth, the underlying brain differences are accumulating. Sometimes the brain can compensate to make up for the disrupted processes. Eventually though, if the disruption was sufficiently severe, the compensatory processes are no longer enough, and symptoms emerge.
This may likewise explain many cases of autistic regression, in which a young child seems to be developing normally, only to lose abilities, or regress, into autism. Perhaps the initial disruption in brain development continued worsening. Or perhaps the compensatory processes couldn’t keep up.
Given how complex the brain is, it can be very difficult to correct differences in brain development and function that start so early in life. This is why treatment for autism needs to be so intensive, and why early diagnosis and treatment are so important.
Thank you for your question. I hope my answer provides some perspective.
Editor’s note: You may also want to read Avoiding Toxic Exposures During Pregnancy, Risk vs. Cause in Autism and Autism Speaks Environmental Factors in Autism Initiative.
Got more questions? Send them to GotQuestions@autismspeaks.org. Subscribe to Autism Speaks Science Digest to get “Got Questions?” blogs and all our research news and perspective delivered to your inbox.