[edit: 9/26/07]I'm removing this cute pic of a kid with Williams because it is doing something funky with my pagecounts.
People with Williams syndrome "usually have a small upturned nose, long philtrum (upper lip length), wide mouth, full lips, small chin, puffiness around the eyes, and a prominent "starburst" or white lacy pattern on the iris of the eyes."
"Children with WS are more sensitive to music. Upon listening they become more emotionally involved, more attentive, with happy and sad feelings persisting much longer than normal and with greater intensity. This affinity for music, if fostered, can help many overcome developmental problems. Some children with WS can barely write, sign their own names, or navigate a stairway, yet can they learn to execute the slight hand movements needed to play the piano or drums."
I think it's pretty amazing how our myths are based on truth... stay tuned for the next episode in which we explore the scientific basis for vampires! :)
For the more technically inclined, here's a link to the Online Inheritance in Man (OMIM) information on the elastin gene and condition of WS.