1. Department of Neurosciences and Center for Molecular Genetics, University of California, San Diego, La Jolla, CA 92093.
2. Department of Medicine, University of California, San Diego, La Jolla, CA 92093.
3. Division of Medical Genetics and Department of Biochemistry and Molecular Biology, Jefferson Medical College, Philadelphia, PA 19107.
4. Athena Neurosciences, San Carlos, CA 94070.
5. UCLA Mental Retardation Research Center Group at Lanterman Developmental Center, Pomona, CA 91769