Williams syndrome was a diagnosis made (but not the final one!)in the Episode of House "No More MrNice Guy".
http://en.wikipedia.org/wiki/No_More_Mr._Nice_Guy_%28House%29

Franchises are required to protect their copyrights no matter what. If they tried to sue someone for a copyright infringement for that trailer, the judge would cite the previous failure to remove the item from youtube (or wherever) and would then deny them the right to it.

My band wrote a song about this myth called Bloody Mary.
It was La Llorona, until we discovered a different but of folklore that pictures La Llorona not as an evil or vengful spirit, but just mournaful at the loss of her children.
www.myspace.com/undersoul