1. Laboratory of Clinical Neurogenetics, Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany, New York, U.S.A.
2. Department of Neurology, Baylor College of Medicine, Houston, Texas, U.S.A.
3. Departments of Neurology, Molecular and Human Genetics, and the Division of Neuroscience, Baylor College of Medicine, Houston, Texas, U.S.A.