1. From the Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland; and the2National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan.
2. National 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