Received December 12, 2012; accepted December 19, 2012. From the Department of Neurology, Mayo Clinic, Jacksonville, FL (J.F.M.); and Service de Genetique Neuro-Vasculaire, AP-HP, Groupe Hospitalier Lariboisiere-Fernand-Widal and INSERM UMR-S740, Paris, France (E.T.-L.). Correspondence to James F. Meschia, MD, Chair, Department of Neurology, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 3222...