Williams syndrome is a CHROMOSOMAL disorder which has PROFOUND effects, not just on personality but on physical appearance. It isn't all that common.
Please don't diagnose your wife with chromosomal disorders based on her being friendly and anxious and bad at charts. Perhaps she has a learning disability, like tons of other people.
It is a spectrum disorder where individuals with small deletions can be regarded as normal. Fibetera's wife may well have a mild version - the only way to know is to do a DNA test.
I would never diagnose her with anything, I am a software developer not a doctor. It just points me in the way of some research for possible things we could talk to a doctor about.
A close friend of mine has Turner's syndrome, also a chromosomal disorder with potentially severe physical effects (such as "neck webbing").
Fortunately for her, she doesn't exhibit the gross physical abnormalities. So while I do endorse the basic sentiment of your comment, you're not on 100% solid ground.
[0]: https://docs.python.org/3/tutorial/