GYRATE ATROPHY-LIKE PHENOTYPE WITH NORMAL PLASMA ORNITHINE

Purpose: To describe the clinical characteristics of a chorioretinal d isease with a gyrate atrophy-like phenotype and normal plasma ornithin e. Methods: One family with three men who had progressive chorioretina l disease and three additional patients with simplex cases were examin ed clinically and with standard electroretinography, electrooculograph y, and dark adaptometry. Results: In the family, a 70-year-old man and his two sons (39 and 41 years of age) were affected. On ophthalmoscop y, sharply demarcated peripheral patches of retinal pigment epithelium and choroidal atrophy were seen to progress to the posterior pole in the father's eye. in three unrelated men (62, 70, and 80 years of age) , chorioretinal atrophy was present in the mid-and far periphery. Visu al acuity was normal in the two youngest of all six patients; however, electroretinogram and electrooculogram waves were reduced. Advanced v isual field defects and visual acuity loss occurred in the four older patients. Electroretinogram and electrooculogram were reduced, and the dark adaptation thresholds were elevated. In all patients, serum orni thine levels were normal. Ornithine-delta-aminotransferase activity in cultured skin fibroblasts and the apparent Michaelis constant (Km) fo r ornithine and alpha-ketoglutarate were within the normal range in al l patients. Conclusions: A gyrate atrophy-like phenotype can result fr om causes other than deficient ornithine-delta-aminotransferase. Its o ccurrence in three male members in two generations in one family sugge sts an autosomal dominant inheritance in at least some such patients.