[r0ze-at-hn]

Armchair geneticist: So in the group of genes that are deleted in particular LIMK1 stands out. After it is deleted there is only 1 copy behind. The other copy could be less effective as sometimes seen, but Estrogen in particular inactivates LIMK1. So in those with genetics for high estrogen signaling (that they are also known for) are more likely to inactivate the one remaining copy of LIMK1. And then you get the highly verbal, social, poor math & visual-spatial information, outcome. This combo would be more likely to be found in families of HPA Axis issues so anxiety, insomnia, etc I would speculate come along for the ride, more than directly influence that brain development branch. It is always more complicated, but for the curious.

Edit: lol no need to actually poke around just see wikipedia https://en.wikipedia.org/wiki/Williams_syndrome#Cause