My son has Autism as you know. He was tested and his IQ was off the charts.
My situation is probably totally different than yours. The school almost couldn't offer him special needs services because his IQ was so high. He tested 19 points higher in one area than the average.
There were a lot of forms. Tedious meetings. I went straight to the Board of Ed. But I had diagnosis in place before I did so. They come to the table with a budget. They don't like doing it unless they have to just to let you know! LOL
However, here at the public schools, they have started something new and I love it. They have individual groups. There's no more putting a child in a class with 30 others and having them do the same thing. If the child is ahead, he goes in to a group with the advanced. If the child is behind, he goes in to a group with the children who are behind. It works out really well. I think it's a great balance from what I have observed.
The other thing is if the school won't help, here we have advocates in our state that advocate for the child. I don't know what your state offers. At one point, we were looking into getting a professional, private, opinion, and they only take cases referred to by the school, so that turned out to go nowhere.