The genetics professor describes one of the world’s most complex and controversial disorders.

Question: What is autism?

Michael Wigler: Well, there are a triad of rnbehaviors thatrnare the earmarks of autism.  Therninclude difficulty in social interactions, delay in the development of rnspeechrnand communication.  And those arerndistinguishable and repetitive behaviors, almost obsessive-like rnbehaviors.  

The recognition of this triad as a condition we rncall autismrnbegan only in the late ‘30s, and as the diagnostic criteria began to be rnmorernwidely applied, more and more children were being called autistic.  And the definition, I think, I mean,rnwhen people now talk about autism spectrum disorders where a child has rnvaryingrndegrees of these abnormalities.  Itrnis not, in fact, an extremely well-defined disorder.  Itrn has sloppy boundaries to normal behavior.  We allrn know people that are awkwardrnsocially, there are many people who learn language late in life, and we rnall mayrnknow people that have stutters, or have obsessive behaviors, or even rnhangrnwringing.  So there is something ofrna continuum of all three of these things. rnThat’s not a condition whose boundaries are well-defined.  Yet, if you meet a child with autism,rnyou can generally say that there is something profoundly wrong here. 

But it’s a hard disorder to define better than rnthat.  And probably the reason it’s harder torndefine better than that is that the number of genes involved.  The number of underlying causes thatrncan create this triad is very great. rnFor example, the syndrome itself is enormously varied.  And if you have listened to somebodyrnwho studies autistic children—children with autism, you’ll frequently rnhear themrnsay that each child that they see is different than the next.  It’s not really a syndrome in the wayrnthat Down syndrome is a syndrome. rnThere are a variety of genetic disorders that are frequently—you rncanrnalmost tell that the children who have these disorders have the same rnunderlyingrncause, because they’ll actually look alike.  It’s rnnot just Down syndrome that has that property, Progeriarnhas that property.  There are arnnumber of childhood disorders wherernthe children who have these disorders actually look alike.  

That’s not the case in autism.  Eachrn child has—is sort of wonderfully different than thernnext child, so there’s a huge amount of variability.  Andrn I think this has confounded the general public becausernit appears that the rate of autism has been going up so dramatically.  In fact, I think that’s mainly due tornincreased diagnosis.

Recorded April 12, 2010