Is there the chance that some of these disorders were completely different disorders and not autism?
Yes, because autism is defined completely by behavior at this point. There are hints about the biological causes of it, and the assumption is that it is something biological, but there is no clear biological marker. The most consistent finding that has to do with biology is that kids with autism have big heads more often then you would expect, but a lot of other people have big heads. It is not a very specific finding. So it really may be that autism is like a fever, where you can have a fever for a lot of different reasons and is the final common pathway of a lot of different things.
Is fragile X considered to fit in the grouping of autism?
Fragile X is separate in the sense that in fragile X, we know exactly where the gene is that causes the disorder, but many kids with fragile X have symptoms that fall within the autistic spectrum. So if you were defining them purely by behavior, some of them would have autism. However, if you are defining autism as things that we do not know the cause of then fragile X would be excluded because we do know what it is that initiates it. We do not know how to treat it very well yet, but we know where that gene is.
Are children with autism tested for fragile X?
Lord: Almost always. I think that is one of the first things that most physicians do.