What's the Relationship Between Genetics and Autism?Apr 21, 2014
Is there a genetic link to autism? Dr. Hilary Coon, University of Utah research professor of psychiatry, discusses the root of autism and its tie with family genetics. She also speaks about how the current knowledge of genetic risk can impact families with autistic individuals.
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Interviewer: Today on The Scope, we're going to try to understand a little bit better genetics and autism. To help us do that is Dr. Hilary Coon. She's research professor for the University of Utah Department of Psychiatry. Let's talk about genetics and autism. First of all, is genetic risk important for autism? Is it the only thing that could cause autism, is genetics?
Dr. Coon: Well, it's known that genetic risk is important, but definitely risk factors are very complicated. Genetics is only one piece of the puzzle.
Interviewer: So a lot of different things. It's not just one gene, probably?
Dr. Coon: No. Probably hundreds of genes.
Interviewer: Yeah. And it's not, like, in my high school biology class where I could determine who's going to have blue eyes and who's going to have brown eyes?
Dr. Coon: Yeah. Definitely not. So what we like to talk about is genetic risk factors. So having maybe a genetic variant in a gene that increases your risk to some degree, but other people in the population might have that same risk factor and not exhibit any symptoms of the disease at all.
Interviewer: When you say "genetic risk," is that a mutated gene? I mean, what exactly does that mean?
Dr. Coon: So it could be any number of different kinds of genetic mutation such as a single base pair in the genetic code that changes the structure or function of the gene a little bit. It might be something that regulates the expression of a gene. It might be a change in a gene that then regulates other genes. So even at the level of the mutations, it could be quite complicated.
Interviewer: Are these genes generally, if I recall back again to my high school biology class, genes help create cells. They're the map to create cells. Is that correct?
Dr. Coon: A gene could influence the structural element of a cell. It could influence how different chemicals pass in and out of a cell. It could influence how much particular enzymes are created or maybe are regulated in various ways, and in the brain, that could get very complicated.
Interviewer: Yeah. And that's where it happens for Autism Spectrum Disorder patients. It's in the brain. Is that where it's all going on?
Dr. Coon: That's what we think.
Interviewer: That's the knowledge as of right now. So the genetic risks sounds like it's really complex. It's a bunch of different genes. You could have those same different genes. I could have them, but then my environment might affect that. Explain that a little bit more.
Dr. Coon: Maybe a good example of this is some research that I'm working on with some colleagues here where we're trying to figure out whether or not in utero environment might actually affect expression, turning on and turning off, of various genes at certain critical times in development, and would there be prenatal risk factors that could then interact with your genes to make you particularly at risk. So your genes give you a certain road map, and then that environmental exposure could then augment or decrease the way that, that road map could go in various ways, and that's completely dependent on interactions with our environment. And it might not be prenatal. It might be postnatal. We don't really know.
Interviewer: Sure. So the air that you breathe, the food that you consume?
Dr. Coon: Potentially.
Interviewer: Yeah. Are there any other factors that would go into that environment?
Dr. Coon: Definitely. We wouldn't want to rule out any kind of environmental risk as being potential interaction effects, and it's just a hard thing to study.
Interviewer: Yeah. How do you even control all those variables to figure out that one thing that might be one of 1,000 things that causes it?
Dr. Coon: Yeah. You know, from one person to the next, it could be a different thing. It could be at a different time in development. It could be, you know, a different exposure that wouldn't actually be a risk factor for the next guy that's sitting next to you because your genetic map's a little different.
Interviewer: So how do you know when you found that one thing, 1 of 1,000?
Dr. Coon: You know, that's kind of why I'm sitting in the genetics chair because it's a little bit easier than sitting in the environment chair.
Interviewer: Why is that?
Dr. Coon: Well, because it's a little easier to get a handle on trying to get the measurement so we don't have to be quite so controlled about all of the different exposures and all the timing of all those exposures that might be out there.
Interviewer: So, Utah I know is doing a lot to contribute to the studies of genetic risk factors for Autism. What are some of the exciting new things that you'd like to talk about?
Dr. Coon: First off, we collaborate with national and multinational groups. There's a large multinational group called the Autism Sequence Consortium, which is now working on getting very detailed genetic sequence on a large case series and then comparing that to sequence on controls and then using that very, very large sample to try to tease out what might end up being very rare genetic mutations. The other thing that we do that's sort of uniquely Utah is that we have identified several very high-risk, really extended pedigrees using a unique resource here which is called the Utah Population Database, which is a genealogical records from, essentially, the founding pioneers of the Valley.
Interviewer: Yeah. Nothing else exists like it in the United States or the world, from what I understand.
Dr. Coon: Yeah.
Interviewer: It goes back many generations. There's a lot of great information.
Dr. Coon: Yep. We have families that we know are connected to each other, but we don't know everyone in the family, obviously. We don't need to. We just know they're people that are coming through the door, but we know that they're related to one another, say, you know, seven, eight, or nine generations back. What we hope, then, is that within these families that the genetic susceptibility is a little more homogeneous since they're all related through, you know, one common founder that they maybe share some of the same genetic risk factors.
Interviewer: Reoccurring patterns is what you're looking for, right?
Dr. Coon: That's right. So it's kind of, like, taking a magnifying glass to the problem and being able to see it because the genetic risk factor would show up over and over in these related individuals. The other thing that is really interesting about those families is that we have many unaffected siblings. They'll have nuclear families within these big extended families with affected cases and then their unaffected siblings. So their unaffected siblings also tell us things. They might tell us about protective factors, so maybe there's a reason why a couple of kids in the family would show some symptoms and then other kids don't.
Interviewer: Finally, how does current knowledge of genetic risk impact families?
Dr. Coon: I think we're still kind of at the beginning.
Interviewer: It sounds like.
Dr. Coon: Yeah. In the broader sense, just knowing that you might have a risk variant where, "Gee, this might be something that isn't necessarily always associated with a risk 100 percent. I'm not sure that's all that helpful.
Dr. Coon: It might be better to spend your money on really good effective behavioral therapy or, you know, the kinds of things that are actually going to be useful because many of these other variants are just not as well categorized yet, and there's not any treatments associated with them.
Interviewer: Sure. Any final thoughts on this topic? Any take-aways for the audience?
Dr. Coon: Just that, you know, research is a very long process. It's something frustrating, I think, for people coming through our door to not be able to know that we'll be able to give them answers right away. It's even for, you know, a finding that we replicate and we're very convinced of. The research still takes years, and years, and years for that to come fully around to some kind of something that is tangible for families. I recognize that's frustrating.
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