This video is so moving - it is worth watching!  Wow!  

http://www.youtube.com/watch?v=u8fKswURt6

Rett syndrome and mecp2 duplication are caused by defects in the mecp2 gene. In one case there is too much protein ad the other too little. The symptoms are quite different, but similar in ways too. Research for Rett overlaps with research for the duplication.