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Siblings Of Autistic Children At Higher Risk For Autism

Siblings Of Autistic Children At Higher Risk For Autism
If you have an autistic child, the chance of you having a second child with autism is higher than previously thought.

If you have an autistic child, the chance of you having a second child with autism is higher than previously thought. That's according to a new study that finds families with one autistic child have 1 in 5 chance of having a second child with autism. We get the latest from two local researchers who helped in the study - the largest of its kind to date.


Leslie Carver, UC San Diego, Psychology


Karen Dobkins, UC San Diego, Psychology

Study:Journal of Pediatrics; Recurrence Risk for Autism

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This is a rush transcript created by a contractor for KPBS to improve accessibility for the deaf and hard-of-hearing. Please refer to the media file as the formal record of this interview. Opinions expressed by guests during interviews reflect the guest’s individual views and do not necessarily represent those of KPBS staff, members or its sponsors.

CAVANAUGH: I'm Maureen Cavanaugh. It's Monday, August 15th. A low income advocacy group is asking people to boycott because the Internet retailer is resists paying California sales tax. We'll explore more about California's effort to get revenue from Internet sales. And he'll hear about the extreme edge of the new sustainable eating movement, and learn a bit about hunting and gathering here in San Diego. But we begin with the resultless of a new study on autism. The study which included researchers and participants here in San Diego, was the largest of its kind studying the recurrence of autism within families. It's found that the likelihood of families with one autistic child having a second child who develops autism much higher than previously thought. I'd like to introduce my guest, Lesley Carver and Karen Dobkins, both professors of psychology at UCSD. And both took part in the research study. I want to thank you both for coming in today.

SHAW: Thank you for having us.

DOBKINS: Thank you.


CAVANAUGH: Let me start with you, professor Karen Dobkins. What did this study set up to find?

DOBKINS: We studied families in San Diego who had at least one child with autism. Now they had a new baby. And we wanted to find out what was the chance that this new baby born into a family where there was at least one older sibling with autism would develop autism. And we called this the recurrence rate. Like you mentioned a moment ago, we found data pooled across 12 different sites, San Diego being one of the sites, that number, the current rate is about 19%, which is about a one in five chance.

CAVANAUGH: About a one in five chance. And that's significantly higher than what was previously thought.

DOBKINS: It is higher than what was previously thought. But what you have to bear in mind is that the prevalence of autism is also higher than what was previously thought. So the chance of having a child with autism if you already have one is one in five. However, the prevalence of autism in society right now is about one in 110. So there's a lot of autism in society right now. Again, the chance is about 20 fold greater if you already have a kid with autism.

CAVANAUGH: Now, professor Dobkins, this has been called one of the largest studies of its kind, and you mentioned 12 sites. It was international, right?

DOBKINS: Yes, it included a site in Canada as well as Israel.

CAVANAUGH: And how many people took part in it?

DOBKINS: Therapy a total of -- there were hay total of 650 families, and a few of them came from San Diego.

CAVANAUGH: Lesley carver, does the finding that a sibling's chance of having autism is greater, does that point it a genetic cause for autism?

SHAW: It's a little bit hard to say from these results. We've known for a long time that genetics are strongly involved in autism. This particular study only looks at children in the same family. So of course children in the same family are experiencing the same environment, and jeans are always expressed in the contexts of an environment. So this particular study can't separate out genetic causes from environmental causes, although it certainly points in the same direction as a genetic cause. Like I said, from other studies, we know that there is a strong genetic component to autism. But the study doesn't really address that directly.

CAVANAUGH: So this study doesn't necessarily give us more information about a possible genetic link?

SHAW: I think if contributes to the idea that there is one. But it doesn't tell us directly about it or distinguish it from the effects of living in the same family environment as your sibling.

CAVANAUGH: When you talk about living in the same family environment, do we have any clues, any area to go into about what environmental factors might influence this chance of another sibling developing autism?

SHAW: We really don't. A lot of -- 40 years ago, people thought there was something about the way parents treated children, for example, and we know that is not true. There's nothing specific we can put our finger on. There's a lot of research being done looking at things like diet to determine whether those things might trigger autism in somebody who's got a genetic risk for it. But we don't really know right now what kind of environmental triggers there might be.

CAVANAUGH: Privacy carver, how important is this research for parent who is have an autistic child?

SHAW: I think it's extremely important. We already through a risk if you have a family with autism. What this can tell parent system to be on the look out and trust their instincts. So parents of a child with autism know what it looks like, they know what to expect, and they know how to deal with it. So this can really cue them in of what to along for with their younger child.

CAVANAUGH: Karen Dobkins, there seems to be as you mentioned, so many different kinds of autism now, so many more diagnoses, what are some of the symptoms parents should look for when they try to determine if either one of their children is developing this condition or if a second child may be developing some sort of autism?

DOBKINS: People think that one of the earliest sign enforce autism is atypical social interactions. Wee seen it in the laboratory and clinics, and it looks like things like not responding to your name being called, not responding to mom pointing at something, getting -- not responding with a smile when your mom smiles at you. Those are sort of the classic atypical social interactions we can see as early as six months. Some other things that parents should be on the look out for is fixation with certain objects. I'll often talk to parents of a child with autism and they'll say that when their child was very young, and given some little train toy, they would sit and spin the wheels over and over and stare at that, as opposed to using the train appropriately. So mainly atypical social interactions, and atypical interactions with toys.

CAVANAUGH: Now you worked with a family or two that took part in this study; is that right?

DOBKINS: Yes, we work directly with these families.

CAVANAUGH: What were their concerns?

DOBKINS: Well, almost all of the parents who have enrolled in our study know that there's some genetic component to autism. And they understand that this new child that they are enrolling in our study has a greater than average chance of developing autism. And so they're obviously worried that this next child will also develop autism, and they feel somewhat comforted knowing that their job is enrolled in a study that's going to look for early signs of autism and tell the parents if we see anything. And we have, in fact, seen early signs in some kids, and we've notified parents early. And those children were then able to get into intervention programs, and they're fairing better now.

CAVANAUGH: Do we know, for example, if the sibling of a child who has autism develops the same form of autism? Or the same severity?

DOBKINS: That's a very good question. The data to date suggests there's no relationship between the severity in the older sibling, and the severity in the younger sibling, if the younger sibling is to develop autism.

CAVANAUGH: That's fascinating. Professor carver, can you explain the kinds of research that you were involved with? Sort of, like, what kinds of testing and questions you administered to the children and the parents involved in the study?

CARVER: So, for this study, for the paper that came out today, we administered standard tests of cognitive development, IQ tests, and tests of autism. The study that we're doing here at UCSD, all the sites that are involved in the study have specific questions we're asking. And our research looks at the development of brain pathways. We follow the children from when they're very young, looking at visual perception, which is Karen's expertise, face processing, which we both are interested in, and social development, which is more my area. So we did things like measured how they look at different kinds of visual patterns, how kids process different kinds of faces, how they respond to social and emotional cues given by others, which is an area that I'm working in.

CAVANAUGH: And how early can the signs of autism be noticed?

CARVER: So most of the research that people have done in this consortium that was involved in this paper has looked at children who are very young. The children in this study were usually enrolled before eight months of age. It's been very difficult because we haven't found the magic bullet that we thought we would find. By six months of age, most of the data that we have, the children look fairly normal of the kids who go onto develop autism seem to lose some skills between then and 12 months. By 12-month, people seem to have things that reliably predict which children are going to end up with autism. It's certainly not what we wish to find, which is six months of age knowing which kids it was, and getting them involved in interventions as early as possible.

CAVANAUGH: I was just about to say that, because, professor, Dobkins, it's very important then, to adventure early. Why is that so important? Why is that -- noticing a child is developing this anyone and getting in there as soon as possible?

DOBKINS: Well, autism's a development disorder, and the earlier -- we think that you're born with it, then it just takes time before you see the symptoms. But with any kind of disorder, the earlier you provide therapy for it, the better you're going to be in the long run. And so there are lots of studies documenting that the earlier you start intervention in kids with autism, the better they fair later on.

MAUREEN CAVANAUGH: Research studies, of course terribly important, and the papers that result from them, extremely important. But I'm wondering too, about the human dimension of working with the families that you worked with in this study. They must have been sister concerned about what you would find about their second child. They already had a child with autism, right? Tell us a little bit about what that was like.

DOBKINS: Well, it's obviously difficult in the cases where we have found the younger sibling to develop autism. We've had to talk to the parents about that. I'll tell you that in most cases, the parent already knew because again, as Lesley said, these parents already have one child with autism, they already know what it looks like, they've done a lot of homework on autism. And so when that younger sibling starts to show signs, they're pretty aware of it. Some of the parents have come to us before we've noticed it. So yeah, we do work very closely with the parents. It's very sad for the parents when the younger sibling ended up with autism, but most parents are kind of prepared for it, to tell you the truth.

CAVANAUGH: What kinds of decisions can families now make based on the study, the results of your study? ?

CARVER: I mean, I think that obviously there's a decision about whether to have more children, but if you do have more children, I think it's important for parents to keep in mind that 80% of children with a sibling with autism don't get autism. And parents should just be on the lookout, and be careful, and watch their child, and maybe not hover over them, but know the signs and know what to expect, and talk to their doctor about it. And the doctor should listen to the families. These families know a lot, and they need to be listened to.

CAVANAUGH: Quickly, my final question to you, professor Dobkins, there's a lot of information and a lot of new diagnoses being made about autism. And as you say, the numbers seem to be climbing in a sense, but I've also heard it said that this is a very important time for autism in that things -- people are learning a great deal about this condition. And it's an exciting time for people to learn and to move in the direction of really getting some better idea about what's going on.

DOBKINS: Right. And what we've learned a lot about in the last ten years is that there is a strong genetic component. One is from these classical twin studies that ask what is the concordance rate of autism in monozygotic if twins versus dizygotic maternal twins?

CAVANAUGH: So in other words, identical twins have a higher instance of sharing an autistic condition than fraternal twins?

DOBKINS: Exactly. And right there, we learn that there's a genetic component in autism. And there have been some very exciting genetic studies, per se, where blood samples are obtained from these kids. There are many, many large databases in the United States that are collecting blood samples from these families and looking to find the specific genes that are involved in autism. And there are about 15 candidate genes at the moment. And it's complex, and we're not going to solve it tomorrow. But there seems to be a genetic component. And there are probably also environmental triggers that interact with the genes to determine who ends up with autism.

CAVANAUGH: I want to thank you both for coming in and speaking with us today. I've been speaking to professors Lesley carver and Karen Dobkins with UC San Diego's psychology department. Thank you both.

CARVER: Thank you.

DOBKINS: Thank you.