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  • "Why?"

  • "Why?" is a question

  • that parents ask me all the time.

  • "Why did my child develop autism?"

  • As a pediatrician, as a geneticist, as a researcher,

  • we try and address that question.

  • But autism is not a single condition.

  • It's actually a spectrum of disorders,

  • a spectrum that ranges, for instance,

  • from Justin, a 13-year-old boy

  • who's not verbal, who can't speak,

  • who communicates by using an iPad

  • to touch pictures to communicate

  • his thoughts and his concerns,

  • a little boy who, when he gets upset,

  • will start rocking,

  • and eventually, when he's disturbed enough,

  • will bang his head to the point

  • that he can actually cut it open and require stitches.

  • That same diagnosis of autism, though,

  • also applies to Gabriel,

  • another 13-year-old boy

  • who has quite a different set of challenges.

  • He's actually quite remarkably gifted in mathematics.

  • He can multiple three numbers by three numbers

  • in his head with ease,

  • yet when it comes to trying to have a conversation,

  • he has great difficulty.

  • He doesn't make eye contact.

  • He has difficulty starting a conversation,

  • feels awkward,

  • and when he gets nervous,

  • he actually shuts down.

  • Yet both of these boys

  • have the same diagnosis of autism spectrum disorder.

  • One of the things that concerns us

  • is whether or not there really is

  • an epidemic of autism.

  • These days, one in 88 children

  • will be diagnosed with autism,

  • and the question is,

  • why does this graph look this way?

  • Has that number been increasing

  • dramatically over time?

  • Or is it because we have now started labeling

  • individuals with autism,

  • simply giving them a diagnosis

  • when they were still present there before

  • yet simply didn't have that label?

  • And in fact, in the late 1980s, the early 1990s,

  • legislation was passed

  • that actually provided individuals with autism

  • with resources, with access to educational materials

  • that would help them.

  • With that increased awareness, more parents,

  • more pediatricians, more educators

  • learned to recognize the features of autism.

  • As a result of that, more individuals were diagnosed

  • and got access to the resources they needed.

  • In addition, we've changed our definition over time,

  • so in fact we've widened the definition of autism,

  • and that accounts for some of

  • the increased prevalence that we see.

  • The next question everyone wonders is,

  • what caused autism?

  • And a common misconception

  • is that vaccines cause autism.

  • But let me be very clear:

  • Vaccines do not cause autism.

  • (Applause)

  • In fact, the original research study

  • that suggested that was the case

  • was completely fraudulent.

  • It was actually retracted from the journal Lancet,

  • in which it was published,

  • and that author, a physician,

  • had his medical license taken away from him.

  • (Applause)

  • The Institute of Medicine,

  • The Centers for Disease Control,

  • have repeatedly investigated this

  • and there is no credible evidence

  • that vaccines cause autism.

  • Furthermore,

  • one of the ingredients in vaccines,

  • something called thimerosal,

  • was thought to be what the cause of autism was.

  • That was actually removed from vaccines

  • in the year 1992,

  • and you can see that it really did not have an effect

  • in what happened with the prevalence of autism.

  • So again, there is no evidence

  • that this is the answer.

  • So the question remains, what does cause autism?

  • In fact, there's probably not one single answer.

  • Just as autism is a spectrum,

  • there's a spectrum of etiologies,

  • a spectrum of causes.

  • Based on epidemiological data,

  • we know that one of the causes,

  • or one of the associations, I should say,

  • is advanced paternal age,

  • that is, increasing age of the father

  • at the time of conception.

  • In addition, another vulnerable

  • and critical period in terms of development

  • is when the mother is pregnant.

  • During that period, while the fetal brain is developing,

  • we know that exposure to certain agents

  • can actually increase the risk of autism.

  • In particular, there's a medication, valproic acid,

  • which mothers with epilepsy sometimes take,

  • we know can increase that risk of autism.

  • In addition, there can be some infectious agents

  • that can also cause autism.

  • And one of the things I'm going to spend

  • a lot of time focusing on

  • are the genes that can cause autism.

  • I'm focusing on this not because genes

  • are the only cause of autism,

  • but it's a cause of autism

  • that we can readily define

  • and be able to better understand the biology

  • and understand better how the brain works

  • so that we can come up with strategies

  • to be able to intervene.

  • One of the genetic factors that we don't understand,

  • however, is the difference that we see

  • in terms of males and females.

  • Males are affected four to one compared to females

  • with autism,

  • and we really don't understand what that cause is.

  • One of the ways that we can understand

  • that genetics is a factor

  • is by looking at something called

  • the concordance rate.

  • In other words, if one sibling has autism,

  • what's the probability

  • that another sibling in that family will have autism?

  • And we can look in particular

  • at three types of siblings:

  • identical twins,

  • twins that actually share 100 percent

  • of their genetic information

  • and shared the same intrauterine environment,

  • versus fraternal twins,

  • twins that actually share 50 percent

  • of their genetic information,

  • versus regular siblings,

  • brother-sister, sister-sister,

  • also sharing 50 percent of their genetic information,

  • yet not sharing the same intrauterine environment.

  • And when you look at those concordance ratios,

  • one of the striking things that you will see

  • is that in identical twins,

  • that concordance rate is 77 percent.

  • Remarkably, though,

  • it's not 100 percent.

  • It is not that genes account for all of the risk for autism,

  • but yet they account for a lot of that risk,

  • because when you look at fraternal twins,

  • that concordance rate is only 31 percent.

  • On the other hand, there is a difference

  • between those fraternal twins and the siblings,

  • suggesting that there are common exposures

  • for those fraternal twins

  • that may not be shared as commonly

  • with siblings alone.

  • So this provides some of the data

  • that autism is genetic.

  • Well, how genetic is it?

  • When we compare it to other conditions

  • that we're familiar with,

  • things like cancer, heart disease, diabetes,

  • in fact, genetics plays a much larger role in autism

  • than it does in any of these other conditions.

  • But with this, that doesn't tell us what the genes are.

  • It doesn't even tell us in any one child,

  • is it one gene

  • or potentially a combination of genes?

  • And so in fact, in some individuals with autism,

  • it is genetic!

  • That is, that it is one single,

  • powerful, deterministic gene

  • that causes the autism.

  • However, in other individuals,

  • it's genetic, that is,

  • that it's actually a combination of genes

  • in part with the developmental process

  • that ultimately determines that risk for autism.

  • We don't know in any one person, necessarily,

  • which of those two answers it is

  • until we start digging deeper.

  • So the question becomes,

  • how can we start to identify

  • what exactly those genes are.

  • And let me pose something

  • that might not be intuitive.

  • In certain individuals,

  • they can have autism

  • for a reason that is genetic

  • but yet not because of autism running in the family.

  • And the reason is because in certain individuals,

  • they can actually have genetic changes or mutations

  • that are not passed down from the mother

  • or from the father,

  • but actually start brand new in them,

  • mutations that are present

  • in the egg or the sperm

  • at the time of conception

  • but have not been passed down

  • generation through generation within the family.

  • And we can actually use that strategy

  • to now understand and to identify

  • those genes causing autism in those individuals.

  • So in fact, at the Simons Foundation,

  • we took 2,600 individuals

  • that had no family history of autism,

  • and we took that child and their mother and father

  • and used them to try and understand

  • what were those genes

  • causing autism in those cases?

  • To do that, we actually had to comprehensively

  • be able to look at all that genetic information

  • and determine what those differences were

  • between the mother, the father and the child.

  • In doing so, I apologize,

  • I'm going to use an outdated analogy

  • of encyclopedias rather than Wikipedia,

  • but I'm going to do so to try and help make the point

  • that as we did this inventory,

  • we needed to be able to look at

  • massive amounts of information.

  • Our genetic information is organized

  • into a set of 46 volumes,

  • and when we did that, we had to be able to account

  • for each of those 46 volumes,

  • because in some cases with autism,

  • there's actually a single volume that's missing.

  • We had to get more granular than that, though,

  • and so we had to start opening those books,

  • and in some cases, the genetic change

  • was more subtle.

  • It might have been a single paragraph that was missing,

  • or yet, even more subtle than that,

  • a single letter,

  • one out of three billion letters

  • that was changed, that was altered,

  • yet had profound effects

  • in terms of how the brain functions

  • and affects behavior.

  • In doing this within these families,

  • we were able to account for approximately

  • 25 percent of the individuals

  • and determine that there was a single

  • powerful genetic factor