Having been heavily involved in biomed with my son who is ASD, i will be happy to help you find information, there is tons of it out there.
First the GF/CF diet. Whether or not you "think" your child has an intolerance, this diet is the first protocol and should be tried by all kids. The proof is in the pudding so to speak, in that you try the diet and look for physical/behavioural changes. the physical changes are: lessened excema/scratching/histamine type eruptions. Others are reduced constipation or diahhrea. check your child's bowel movements. Does he have undigested food in his poo? Is it full of mucus?
These are signs of intestinal inflammation. My own nutritionist says all kids with ASD should be on the diet despite any testing cause the tests are not infallible. There is no REAL known test for gluten/casein intolerance and there is much speculation about them. Really you just have to go for it and see what happens. The diet wont hurt your child, it can only help. Our whole family is now gluten free and we feel much better.
On the gut stuff, do your research about "leaky gut". If you understand the science behind why our kids cant tolerate gluten/casein then it all makes sense. Buy yoursef this book "Children with Starving Brains, by Jacqueline McCandless. It is the biomedical interventions for autism "bible". and it tells you everything you ever wanted to know (go to amazon.co.uk?tag=mumsnet&ascsubtag=mnforum-21 - its about £12.00)
Your "gut" supplies 60 percent of your immune system. If it is out of whack, so is the rest of your body. If your body is not absorbing minerals and vitamins or is "leaking" molecules into the bloodstream that shouldnt be there, then you have a problem. That is what leaky gut is all about. Our kids may be leaking molecules of milk and wheat into the blood stream, these molecules find their way to the brain and the brain says, heyy,hold on what are you doing here, and the brain reacts by putting the child into an opiate like state. Tons of research on this.
But thats only the beginning. Once you heal the gut (which for many kids is a lifelong battle) then you have to look at minerals/vitamins, toxic metals, and other nasties. Much research points to autism being a result of the body not being able to detoxify itself. Where you or i can get rid of toxins, our kids cannot.
so you take a kid who is constipated for 7 days, and he is re absorbing all the crap (literally) from his system back into his system and you get a kid loaded with nasty stuff who cant think, who acts out and is not learning.
There is no time limit to starting biomed and the diet. Now would be good.
go to: www.treatingautism.com. This is a UK site and attached to this site is a great yahoo discussion forum where you can learn from other parents.
By the way, get your child's bloods done for free with the NHS. Demand that they check liver, kidney, thyroid, etc. Then you will have a better picture of what is going. There are loads of tests that you can get done through IWDL a lab in the UK. Get a nutritionist or DAN doctor who knows what they are doing and away you go.
I fervently believe my son's autism is a result of his inability to detoxify and an accumulation of heavy metals, toxins and other environmental assaults. He is getting better every day and is totally NOT the little boy he was 2 years ago. All thanks t biomed.
sorry, went on so long, but there is just so much out there now. Its nothing like it was 10 or 15 years ago. Autism is treatable.