1. From Duke University Eye Center and the Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina;
2. Massachusetts Eye and Ear Infirmary and the Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts;
3. Center for Human Genetics and Department of Medicine, Duke University Medical Center, Durham, North Carolina; and
4. Center for Human Genetics Research, Vanderbilt University Medical Center, Nashville, Tennessee.