On Frontline, a Personal Look at Parkinson's

As one of the researchers says in this story, there's an old saying which is that genetics loads the gun, but environment pulls the trigger. And that may be part of what plays out with Parkinson's

As Michael J. Fox likes to say, we each get our own customized version of the disease, but unfortunately none of them come with operating instructions.

http://www.pbs.org/newshour/bb/health/jan-june09/parkinsons_02-03.html