Autism Rate in Siblings Higher Than Thought


If you have one autistic child, your chances of having another child on the autism spectrum are even greater than previously thought, according to a new study from Pediatrics. While the recurrence risk of autism had been previously estimate at 3 to 10 percent, researchers from the University of California at Davis MIND Institute have found that the recurrence risk of 18.7 percent if the younger sibling is a boy and 9 percent if the young sibling is a girl.

The study is the largest to look at the risk of the younger sibling of an autistic child also being diagnosed with autism, says NPR. 664 infants with an older biological sibling with an autism spectrum disorder were followed from early in life to 36 months, at which point they were diagnosed as being autistic or not.

If a family already has two autistic children, a young sibling has a 1 in 3 chance of being diagnosed with autism.

One reason for researchers finding an increased risk of a young sibling being autistic is that†the criteria for an autism spectrum diagnosis are broader than in the past. A younger sibling might be diagnosed with Asperger’s Syndrome, for instance, and have an average or higher IQ and be able to attend mainstream schools; in the past, clinicians might not have seen such a child as being on the autism spectrum. Due to all the attention cast onto autism in the past decade, people have a much better understanding of the neurodevelopmental disability and are thus more likely to detect autism in a child, especially if they know the child has an autistic sibling.

My 14-year-old son Charlie is our only child; we decided only to have only him for a number of reasons. Charlie received a diagnosis of severe autism when he was just about two years old (well, the team at the Minneapolis Children’s Hospital who diagnosed him didn’t actually say “severe autism” but gave us a general sense of “this kid is a really bad case”). He can talk a very little, can’t really read, has lots of academic and communication and behavioral challenges; just a few years ago a school behavior consultant was recommending a “temporary residential placement” for him. We wanted to be able to devote all of our resources to taking care of Charlie, whose early years of therapy costed about the same as private college tuition. We knew that if we had another autistic child, I would not be able to work. We’ve moved several times (including, once, into my in-laws’ house) to find the best educational opportunities for Charlie. A sibling would have found that his or her life completely revolved around Charlie’s care.

Frankly, I wasn’t really surprised to learn about the higher rates of autism found in younger siblings of autistic children, nor was my husband. We’ve long thought the estimates of 3 to 10 percent were low and know several families with more than on autistic child. In some cases, the children’s autism diagnoses are at different levels of severity on the autism spectrum (one child might have Asperger’s and the other autism; the child with Asperger’s might only have been diagnosed after their younger sibling was diagnosed).

With all this said, I hope that people won’t rush to judgement regarding the study and that families with one autistic child won’t have dire warnings issued to them about the risks of having another autistic child. Life with Charlie is never easy but we really do know so much about autism today and, especially, about how to teach and help autistic children and individuals. We still have a long way to go and certainly can do a lot better in creating the best possible schools, services and residential and job options for autistic adults. It was scary learning that 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.

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Photo by hepingting


K s Goh
KS Goh6 years ago

Thanks for the article.

Miriam M.
Miriam Mason6 years ago

Autism is NOT genetic. The evidence against genetic causes is overwhelming and much heavier than any other evidence. Vaccines are only one environmental insult that contributes. My situations was having a mouth full of mercury fillings and vaccines while my children where in utero. Genetics can predispose you to being much more vulnerable, but in the end, we'll all be poisoned and have poisoned children unless we stop playing the denial game with ourselves and actually change our ways.

Cat W.
Past Member 6 years ago

It was Monsanto who created Agent Orange, and who continues to poison our earth and our bodies with pesticides, and genetically modified foods that have leaked into every avenue of our food sources. Think you're living a GMO-free life?? You're not. We're all guinea pigs; free lab rats for Monsantos world-wide domination.

Carol B.
Carol Burk6 years ago

It IS scary, but there are scary things that can happen with any baby. Cancer, or crib death, to name a couple of the scariest. Developmental disabilities can come from genetic conditions, a mild illness in the mother during the early part of her pregnancy, or birth complications. And possibly many "developmental issues" are not considered serious enough to be "an issue" – he is just a bit of a slow learner, she is just a bit over-active, he can't do maths, she can't read well... And now we have the Alphabet Diagnoses: ADD, ADHD, and eventually maybe LMNOP and XYZ. Just to remember that our children are OUR CHILDREN, not the idealized children of the diaper ads. And they are precious to us, whether they learn to read or write or speak or walk.

Joy Looney
Joy Looney6 years ago

This only makes sense right? Parents really need to think twice and more and have genetic counseling done if they have already had one autistic child and are thinking of having another child. With the amount of attention and care even one autistic child needs it is unfair to bring another child into the world with the same.

colleen p.
colleen p6 years ago

Suzanne H., because people would rather stick to the vaccine scare.

Miriam M.
Miriam Mason6 years ago

Nobody has looked at maternal body burden/illness. But it's obvious this is what is happening. In 1999, the CDC stated openly that 1 in 6 women has such a high mercury body burden that damage will be done to a fetus during pregnancy. Children of such burdened mothers are being born predisposed and then we are upping the anti by introducing ethyl mercury into their bodies via shots and lo and behold -- prepoisoned children getting sick. Imagine that. Too many generations in our industrial technological age have damaged us and our ability to procreate in the manner we had in the past.

Serious food for thought.

Suzanne H.
Suzanne H6 years ago

You know, I think Dupont was the company who developed Agent Orange....After Viet Nam they sold a watered down version of this deadly chemical to farmers to ward off pests.............Which has been proven to interrupt nuro transmitters in our young...............Why is this not being investigated?