Two patients with genetically confirmed spinocerebellar ataxia type 7 (SCA7) presented with progressive visual loss. Examination disclosed substantial visual acuity loss, central scotomas, and marked dyschromatopsia. Ophthalmoscopic abnormalities were subtle, with only mild retinal artery attenuation and minimal foveal region pigmentary abnormalities. Both patients had slow saccades and partially limited ductions, although neither reported diplopia. One patient had obvious extremity and gait ataxia, but the other had only an unsteady tandem gait. Results of electroretinography (ERG) were abnormal in both patients. These cases illustrate that SCA7 may present with profound visual loss yet minimal ophthalmoscopic findings and sometimes minimal ataxia. The clues to diagnosis are the abnormal color vision, retinal artery attenuation, abnormal eye movements, and a family history of similar manifestations, which may have gone undiagnosed. Full-field or multifocal ERG will always disclose photoreceptor dysfunction. Genetic testing is now available to confirm the diagnosis.
Departments of Neurology (MJT, RJL) and Ophthalmology (EB, RLT), University Hospitals Case Medical Center, Cleveland, Ohio; Daroff-Dell'Osso Ocular Motility Laboratory (MJT, RLT, RJL), Louis Stokes Department of Veterans Affairs Medical Center, Cleveland Ohio; and Departments of Ophthalmology (JAF, VB, NJN), Neurology (VB, NJN), and Neurological Surgery (NJN), Emory University School of Medicine, Atlanta, Georgia.
This study was supported in part by a departmental grant (Department of Ophthalmology) from Research to Prevent Blindness, Inc., New York, and by core grants (P30-EY06360, Department of Ophthalmology) from the National Institutes of Health (NIH), Bethesda, MD. Dr. Newman is a recipient of a Research to Prevent Blindness Lew R. Wasserman Merit Award. Drs. Leigh and Thurtell are supported by NIH Grant EY06717, by the Department of Veterans Affairs, and by the Evenor Armington Fund.
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Address correspondence to Nancy J. Newman, MD, Neuro-ophthalmology Unit, Emory Eye Center, 1365-B Clifton Road NE, Atlanta, GA 30322; E-mail: firstname.lastname@example.org