BlueSky,
I will probably see this inside-out or upside-down compared to other folks here, but as the mom of a 2e child with an expressive language disorder, my first thought when looking at the scores is - is it possible that there is a component of expressive language challenge that is driving what appears to be selective mutism, which in turn is related to the discrepancy in VCI vs PRI scores on the WISC.
At home, she talks non-stop, is a comedian, displays her intelligence, etc., etc. At school she speaks the bare minimum, rarely elaborates, etc., etc.
This was also true of my ds when he was in early elementary school. We had no idea he had any type of expressive language challenge because at home, he talked to us all the time - and I mean ALL the time. At school, he would clam up and barely be able to utter a whisper if he had to talk to a teacher, and in peer groups he was an observer, rarely contributing anything verbally unless directly asked. We chalked all of that up to personality. Parallel to that, he was not completing work we'd expected him to be capable of doing easily at school, and we chalked that up to what we thought was perfectionism. Because of the nature of our ds' challenge, his communication challenges first became apparent as challenges with written expression. It wasn't until he was around 9 years old, in 4th grade, that he was able to tell us that he didn't know what to say in the situations at school etc where he needed to talk but was so quiet. What looked like shyness or anxiety was actually an inability to generate words.
At home, he had no issues - but at home, we weren't requiring the same type of communication. He was talking non-stop about ideas he had in his head and could clearly express. At school and in peer groups, other people were controlling the conversation and asking him for information - it's a very different type of communication skill and knowledge.
I'd take a look at the types of communicating/talk your ds produces at home vs the types of communication expected of him at school. If you think that any of what I said might make sense, you might consider having your ds evaluated by a speech language pathologist (if he hasn't already had an SLP eval).
She also suffers from high anxiety and is a perfectionist and hates to get things wrong.
My ds also suffered from extreme anxiety in early elementary, before we fully understood the nature of his challenges. I probably wouldn't even think twice about the note that your dd has selective mutism or is a perfectionist except for the two relative "lows" showing up on her WISC - in VCI and also PSI. It was a challenge related to Processing Speed that led us (parents) as well as teachers to think our ds was a perfectionist. In reality he was struggling with output.
It's possible none of this is relevant for your ds, but fwiw, possibly something to consider.
Best wishes,
polarbear
