[1] Univ Toronto, Div Neurol, Toronto, ON, Canada
[2] Vall dHebron Univ Hosp, Barcelona, Spain
[3] Univ Calif San Francisco, San Francisco, CA 94143 USA
[4] Genentech Inc, San Francisco, CA 94080 USA
[5] F Hoffmann La Roche Ltd, Basel, Switzerland
[6] Baden Wuerttemberg Cooperat State Univ, Lorrach, Germany