1. From the Molecular Genetics Unit (M.M., A.S.), Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Porter Neuroscience Research Center, Bethesda, Md; the Section on Biostatistics (W.M.B.), Department of Public Health Sciences, Wake Forest University Health Sciences, Winston-Salem, NC; the Reta Lila Weston Institute of Neurological Studies (J.A.H.), Institute of Neurology, University College London, London, UK; and the Department of Neurology (J.F.M.), Mayo Clinic...