The Sunday NY Times is carrying a very long article about Williams syndrome by David Dobbs. I think it's a nice article, beginning with some anecdotes relating the lives of people with Williams, and then proceeding into the science:

After being ignored for almost three decades, Williams has recently become one of the most energetically researched neurodevelopmental disability after autism, and it is producing more compelling insights. Autism, for starters, is a highly diverse spectrum disorder with ill-defined borders, no identified mechanism and no clearly delineated genetic basis. Williams, in contrast, arises from a known genetic cause and produces a predictable set of traits and behaviors. It is an experiment of nature, as the title of one paper puts it, perfect for studying not just how genes create intelligence and sociability but also how our powers of thought combine with our desire to bond to create complex social behavior a huge arena of interaction that largely determines our fates.

Also, the story of J. C. P. Williams himself presents an unsolved mystery:

Williams syndrome was first identified in 1961 by Dr. J. C. P. Williams of New Zealand. Williams, a cardiologist at Greenlane Hospital in Auckland, noticed that a number of the hospitals young cardiac patients were small in stature, had elfin facial features and seemed friendly but in some ways were mentally slow. His published delineation of this syndrome put Dr. Williams on the map off which he promptly and mysteriously fell. Twice offered a position at the prestigious Mayo Clinic in Rochester, Minn., he twice failed to show, disappearing the second time, in the late 60s, from London, his last known location, with the only trace an unclaimed suitcase later found in a luggage office.

Wow, that's weird. I couldn't find any more details on the disappearance.