1. From the Departments of Medicine (Division of Medical Genetics) (G.P.J., R.J.R., R.J., V.H.B., S.M., C.E.F.), Epidemiology (G.P.J.), Genome Sciences (G.P.J., C.C., M.R., D.N., C.E.F.), Neurology (G.D.S.), and Biostatistics (P.J.H.), University of Washington, and the Puget Sound Veterans Affairs Health Care System (T.S.H., G.D.S.), Seattle, Wash.