I can't even imagine the despair associated with having a child with Autism. I do have a child with brain trauma though and it is tough. I understand that anyone in your position would want answers.

This was a study from March on Autism - I suspect you follow the science - but I'll post this anyway:

http://www.lef.org/newsletter/2014/0304_Mechanism-proposed-that-links-decreased-levels-vitamin-D-and-serotonin-found-in-autism-patients.htm

Dr. Cannell of the Vitamin D Council has worked closely with autistic children. He himself is on the spectrum and this was always of special interest to him.

He has long suspected that Vitamin D3 deficiency was behind the Autism epidemic. This was for two reasons:

First, because the onset of the epidemic exactly coincides with the sun-scare campaigns that were instituted in the 1980's when everyone began to use sunscreen - which blocks Vitamin D3. (Other chronic conditions spiked at the same time - diabetes, heart disease and cancers for instance. Research shows they are all VD3 sensitive chronic conditions.)

Second, because one of the groups at highest risk are the children of those at the higher end of the socio-economic scale. That is contrary to all other known diseases. They were able to determine however, that this group of financially comfortable, highly educated parents were the most likely to be very faithful about slathering themselves and their children with sunscreen.

Autism most often occurs prenatal in a Vitamin D3 deficient mother.

This is not the only research that connects the two - there is actually a great deal of research on this now. And Harvard is currently running a study on this as well. (Different from the one from Harvard on Autism at the Council's website.)

Dr. Cannell's work with autistic children had specific results. Notable observations were that once an Autistic child's blood serum levels VD3 had been brought up to "life guard" range (90-100 ng/ml) - two things happened. They would begin talking in complete sentences, and they would begin socializing.

This is a reflection of the fact that Autistic children notably do better in the summer anyway.

Dr. Cannell used to treat Autistic children for free - and he may still. A call to the Vitamin D Council would be the way to find out. They are on the web:
www.vitamindcouncil.org

Also - here is a search at the Council's website on Autism, that shows a collection of studies they shared with their readers.

http://www.vitamindcouncil.org/?s=Autism&submit=Submit#

And you can also search the Vitamin D Council's website for the "Autism Letters" - letters from parents of autistic children to Dr. Cannell. They are amazing letters.