Just searched for #WilliamsSyndrome Found only two old toots, that had to do with diagnostics.
I guess there's no Mastodon community for people with Williams, or their family members, yet.
So, In the spirit of creating community:
Hi! I'm a dad of a girl with Williams Syndrome. Anyone with a family member who has it, of if you have it yourself, you are most welcome to toot at any time!