This work was supported by grants from the National Institute of Health and the National Institute on Aging: R37-AG15473, P01-AG07232 (RM), R01-AG09029, P30-AG13846 (LF), P20-RR11126 (IJ), the Alzheimer Association, The Blanchett Hooker Rockefeller Foundation and The Charles S. Robertson Gift from the Banbury Fund (RM). The laboratory under the direction of Dr. St George-Hyslop received additional support from the Alzheimer Society of Canada, Japan-Canada and Canadian Institutes of Health Research Joint Health Research Program (ER), the Canadian Institutes of Health Research, Alzheimer Society of Ontario, Howard Hughes Medical Institute, Canada Foundation for Innovation (PH), Fonds de la Recherche en Santé (YM).