1. M. H. Polymeropoulos, S. E. Ide, A. A. Schaffer, R. L. Nussbaum, Laboratory of Genetic Disease Research, National Center for Human Genome Research, National Institutes of Health, Bethesda, MD 20892-1430, USA.
2. J. J. Higgins and L. T. Pho, Clinical Neurogenetics Unit, Medical Neurology Branch, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1430, USA.
3. L. I. Golbe, W. G. Johnson, E. S. Stenroos, A. M. Lazzarini, R. C. Duvoisin, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
4. G. Di Iorio and G. Sanges, Istituto di Scienze Neurologiche, Facoltá di Medicina, Seconda Universitá degli Studi di Napoli, Naples, Italy.