1. From the Guerrieri Center at the Wilmer Eye Institute, the
2. From the Guerrieri Center at the Wilmer Eye Institute, the2Neuroscience, and the
3. From the Guerrieri Center at the Wilmer Eye Institute, the3Departments of Molecular Biology and Genetics and2Neuroscience, and the4McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.