Occasionally you come across articles about rare diseases and I often find them captivating. This one is particular is amazingly well written and reads almost like a short story. This is about a rare disease called FOP or Fibrodysplastia Ossificans Progressiva. There have been ~700 confirmed cases in the world.

 

http://www.theatlantic.com/magazine/archive/2013/06/the-mystery-of-the-second-skeleton/309305/