Clinical study of a large family with autosomal dominant progressive cone degeneration.

PURPOSE: Autosomal dominant cone degeneration is an uncommon disorder characterized by progressive photophobia, hemeralopia, decreased central vision, and dyschromatopsia. To better understand the variable expressivity of autosomal dominant cone degeneration, we studied a single, large family. METHODS: We performed comprehensive ophthalmic examinations, full-field electroretinography, foveal electroretinography, and color vision studies on 73 family members. RESULTS: Of the 73 family members, 34 were affected. Symptoms generally began in the first decade of life and slowly progressed into midlife. Ophthalmoscopic findings consisted primarily of macular atrophy. The photopic full-field electroretinogram was important in establishing the diagnosis, although the results of the electroretinograpic measurements varied across individuals. Either the foveal electroretinogram amplitudes were abnormally low or the foveal/parafoveal ratio was abnormal in all affected subjects. CONCLUSIONS: No single test or finding was completely sensitive or specific for accurate diagnosis of autosomal dominant cone degeneration. Especially in the more mildly affected subjects, a constellation of symptoms, findings, and test results were used to diagnose autosomal dominant cone degeneration accurately.