1. Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School; 165 Cambridge Street, Suite 600, Boston Massachusetts 02114 USA
2. Department of Neurology; Harvard Medical School; Boston Massachusetts USA
3. Department of Neurology; University of California; Irvine, Orange California USA
4. Department of Neurology; Augusta University Medical Center; Augusta Georgia USA
5. Department of Neurology; Methodist Hospital; Houston Texas USA
6. ALS Therapy Development Institute; Cambridge Massachusetts USA