1 Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
2 Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
3 Department of Neurology, Date Red Cross Hospital, Date, Japan.
4 Department of Neurology, Japanese Red Cross Asahikawa Hospital, Asahikawa, Japan.
5 Sapporo Neurology Hospital, Sapporo, Japan.
6 Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, Japan.
7 Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan. yabe@med.hokudai.ac.jp.