1. Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701, USA.
2. Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
3. Isis Pharmaceuticals, 1896 Rutherford Road, Carlsbad, CA 92008, USA.
4. Department of Neurology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02114, USA.