1. From the Department of Population and Quantitative Health Sciences (E.M.), Case Western Reserve University, Cleveland, OH; Biogen (Y.H., S.L., N.S., E.F., A.G., H.R., E.T., P.G.B.), Cambridge, MA; Human Genetics and Bioinformatics (X.J., A.H., T.B.), Genentech, San Francisco, CA; and Department of Public Health Sciences (F.B.B.), University of Miami, FL.