1. From the Department of Pathology (J.C., D.L.Q., K.S., K.E.B.), Emory University, Atlanta, Ga; Institut National de la Santé et de la Recherche Medicale Unit 36 (P.C.), College de France, Paris, France; and Howard Hughes Medical Institute (M.R.C.), Eccles Institute of Human Genetics, University of Utah, Salt Lake City, Utah.