N Engl J Med 2008 Jul;359(5)
Departments of Internal Medicine (T.G.L., B.C.C.), Mathematics (F.R.A.), Biology (F.R.A.), and Pediatrics (T.G.L.), and the Intermountain Cystic Fibrosis Center (T.G.L.) and the Lung Transplant Program (B.C.C.), University of Utah, Salt Lake City; and Nuffield College, Oxford, United Kingdom (D.R.C.).