1. Department of Pediatrics and Center for Molecular Genetics, M-034, University of California School of Medicine, La Jolla, CA 92093.
2. Department of Neurosciences, M-024, University of California School of Medicine, La Jolla, CA 92093.
3. Molecular Neurogenetics, E. K. Shriver Center, Waltham, MA 02254' Laboratory of Neurogenetics, Massachusetts General Hospital, Boston, MA 02114; and Neuroscience Program (Neurology), Harvard Medical School, Boston, MA 02115.