[1] Seoul Natl Univ, Seoul Natl Univ Hosp, Dept Neurol, Stem Cell Res Ctr,Neural Stem Cell Lab,Clin Res I, Seoul, South Korea
[2] Korea Ctr Dis Control & Prevent, Div Epidem Intelligence Serv, Seoul, South Korea
[3] Seoul Natl Hosp, Ctr Alcohol & Drug Addict Res, Seoul, South Korea
[4] Pohang Univ Sci & Technol, Div Mol & Life Sci, Pohang, Kyungbuk, South Korea
[5] Eulji Univ, Sch Med, Eulji Gen Hosp, Dept Neurol, Seoul, South Korea
[6] Ajou Univ, Brain Dis Res Ctr, Suwon 441749, South Korea
[7] Univ British Columbia, UBC Hosp, Dept Med, Div Neurol, Vancouver, BC V5Z 1M9, Canada