The Fragile X autism connection

I did a quick google search, and the articles I found indicated that while there may be some symptom overlap, there are also some markedly different symptoms between the two. Which means that treatment and interventions for those specifically different symptoms need to be different between FXS kids and ASD kids - in fact if you confuse the diagnosis and use the wrong treatment, in some cases it would be counterproductive not just unproductive. So I don't see how there can be a one causes the other connection. I do think that there are a lot brain disorders that have some similar malfunctions, or malfunctions in similar parts of the brain, but that does not necessarily imply causation of one for another.