New Study Shows Higher Autism Rates for Autism Siblings

How likely is a child with autism to have an autistic sibling? The medical journal Pediatrics recently published results from the UC Davis MIND Institute's Infant Sibling Study, showing that nearly 20 percent of 664 infant siblings of children with autism -- infants who were tracked and evaluated from age six to thirty-six months -- developed an autism spectrum disorder. This rate is much higher than previous estimates of three to ten percent.

Parents' reactions to the study varied. "Makes me nervous!" tweeted MarfMom, whose two-year-old son with autism has an eight-month-old infant brother.


India at One Year, Leo - who has autism - at Five


Personally, I wasn't surprised by the higher numbers -- in the autism community, families with multiple members on the spectrum are not uncommon, so the new findings seem more realistic than the previous rates of ten percent or less. And an autism spectrum diagnosis isn't limited to kids like my son Leo, whose autism is not subtle -- the diagnosis includes people such as John Elder Robison who have quirky but functional communication and social skills and do not consider themselves disabled. An autism diagnosis doesn't necessarily limit a child's future.

Still, the new percentages were newsworthy. Shots, NPR's Health Blog, covered the study in its story Autism Risk 'High' For Kids With Older Sibling With The Disorder, which is the headline that made MarfMom nervous and had me advising parents on Thinking Person's Guide to Autism Facebook page discussion to focus on positive implications: "The headline is an attention grabber, but the takeaway is for increased pediatrician scrutiny of younger autism siblings, for earlier support if needed."

Indeed, as reported in the NPR Shots story,

[Study director] Ozonoff says maybe the most important message is for pediatricians. "If they have a little boy in their practice who has an older sibling [with autism], that child's risk is 25 times higher than another infant in their practice," she told Shots. "This should mean there is more careful monitoring and screening beyond the usual questions at a normal well-child visit," Ozonoff continues. "Drilling down into the things that we know are early signs of autism -- interest in people, responding to their name, responding to other people, smiling at other people."

That need for increased attention to infant sibling development is what many parents are responding to. As Alysia Krasnow Butler of Try Defying Gravity stated on that Facebook thread:

"We just went through this in our house. Our youngest was watched more closely because of studies like this, and we got into a developmental eval more quickly because of it. Returned last week with a PDD-NOS diagnosis, and now have the opportunity for earlier intervention."

I understand nervous, concerned parents of autism siblings. I've been them. My husband and I found out I was pregnant with our third child less than a year after our second child's autism diagnosis. Since we were new to the world of autism, and we had fallen in with less-than-ideal autism attitude role models, our primary emotion was fear -- fear that the baby might have autism, too.

I'm not one to sit around and wring my hands when there are other options, so we took action. When our third child was born, we enrolled her in the MIND Institute Infant Sibling study -- yes, our Mali is one of the 664 babies in the Pediatrics report.

I can't tell you how comforting it was to be able to do something, to hand my baby over to researchers whose entire focus was determining her exact developmental levels according to tests like the Mullen Scales of Early Learning and the Vineland Adaptive Behavior Scales. I was so grateful to receive updates every few months with specific information about how she was progressing. Here's an excerpt from Mali's twelve-month report, when she was that baby in the photo above:

"Age-appropriate skills [Mali] showed us included pretending to drink from a cup [...], playing peek-a-boo, combining jargon with a gesture, and saying several words. In summary, [Mali's] performance was developmentally normal with no concerns."

Mali completed the entire longitudinal study, participating from age six to thirty-six months. Her social and communication behaviors were pronounced "concern-free" at the end of the study. We exhaled.

But what if Mali hadn't been neurotypical? What if the researchers had flagged her development, and told us she was at risk for autism? Well, we would have had the information we needed to support her at the earliest possible stages. That's where I hope study results like these will lead, for today's ASD-diagnosed autism siblings. To increased attention, to and awareness of autism symptoms in children with elevated diagnosis likelihood. As Kristina Chew blogged at

"It was scary learning that [my son] Charlie was autistic twelve years ago but I hope parents might know that there is always a lot of hope and more so than ever today."

I agree. When it comes to autism, hope is critical, and there's definitely more hope springing about than when Charlie and Leo were diagnosed -- as well as more community, more awareness, more acceptance, and more visibility. All factors that, along with an early diagnosis, can help lead all our children with autism towards the best possible lives.


Shannon Des Roches Rosa writes about parenting all three of her rascally and probably overly-evaluated children at,, and

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