1. From the Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland; and the2Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan.
2. Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan.
3. From the Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland; and the