Reply #1: "the cause of each person's disease will be unique"

[pnwmom]

which is why it is been so difficult to tease out the cause of autism -- there isn't a single cause.

This is interesting:

"Two other clear-cut patterns emerged when the scientists compared the autistic and healthy brains. First, the autistic brain showed a drop in the levels of genes responsible for neuron function and communication. Second, the autistic brain displayed a jump in the levels of genes involved in immune function and inflammatory response."

Immune function and inflammatory response. This is why Hannah Poling's vaccine reaction triggered her autism syndrome -- she had an immune system disorder. Immune system disorders appear to be one of the things that, often in combination with other risk factors, can increase the risk of autism syndrome.