This is a terrible disease whose causes have remained unclear and for which no treatment exists, ... Our findings provide convincing support for a genetic basis. But it's more than that -- development of the disease takes a second hit. One such hit is cigarette smoking.  -   Mark Steele     Quotes
This is a terrible disease whose causes have remained unclear and for which no treatment exists, ... Our findings provide convincing support for a genetic basis. But it's more than that -- development of the disease takes a second hit. One such hit is cigarette smoking. Mark Steele
 Causes