1. From the Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania;
2. MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, Scotland, United Kingdom;
3. Gene Therapy Program, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
4. Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland.