As a mother of an almost 8 year old with autism, let me support the previous
post re celiac and casein. Some of our kids don't test positive for classic
celiac. They do have neurological rather than solely GI allergic reactions to
gluten and casein. They are just as gluten (and casein) intolerant, but it
doesn't necessarily manifest itself the way traditional celiac does. To
provide the mother with more info, apparently the proteins get into the
bloodstream, go to the brain and can look like pseudo-neurotransmitters.
Gluten tends to make the child tantrummy and inflexible, casein can seem to
have less effect until  you try a classic challenge, then you can really see
what it's doing to your child. Be very strict about the casein for 2 weeks or
so, then let him have something really toxic like macaroni and cheese (both
gluten and casein) your child may look more psychotic than autistic as a
result. You may not want to bother to try this as it's very scary and not too
great for the kid. Also, try epsom salt baths at night, every night for 2
weeks or so while maintaining a STRICT gluten and casein free diet, see what
happens to the childs language and then let me know. Many parents doing this
have seen dramatic to subtle improvement in mood, cooperativeness and
language, as well as motor skills.  Sorry if this has all been discussed in
earlier posts. Candace