Kenji Ozawa1, Kiyofumi Mochizuki2, Yusuke Manabe2, Nobuaki Yoshikura3, Takayoshi Shimohata3, Ichizo Nishino4, Yu-Ichi Goto5,6. 1. Department of Ophthalmology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan. kj-ozawa@umin.ac.jp. 2. Department of Ophthalmology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan. 3. Department of Neurology and Geriatrics, Gifu University Graduate School of Medicine, Gifu, Japan. 4. Departments of Neuromuscular Research, National Institute of Neurology and Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan. 5. Mental Retardation and Birth Defect Research, National Institute of Neurology and Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan. 6. Medical Genome Center, National Center of Neurology and Psychiatry, Tokyo, Japan.
Abstract
PURPOSE: Mitochondrial encephalopathy with lactic acid and stroke-like episodes (MELAS) is caused by mutations in the mitochondrial DNA. Approximately 80% of MELAS patients have an A > G transition mutation at nucleotide pair 3243 in the mitochondrial DNA, m.3243A > G. There are also MELAS patients with a one-base deletion at nucleotide pair 3271 in the mitochondrial DNA, m.3271delT, but these cases are very rare. We report a case of MELAS with the m.3271delT and describe the retinal structure and electrophysiological alterations. METHODS: The retinal structure and function of a 37-year-old woman who was referred to our clinic for of nyctalopia were studied. Standard ophthalmological examinations including the medical history, measurements of the best-corrected visual acuity, intraocular pressures, and slit-lamp biomicroscopy, ophthalmoscopy, fluorescein angiography, fundus autofluorescence, spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (ERG), and multifocal electroretinography (mfERG) were performed. RESULTS: Fundus examination showed bilateral hypopigmentary changes of the retinal pigment epithelium which extended from the posterior pole to the equator. Fluorescein angiography showed patchy hyperfluorescence due to window defects at the atrophic areas. Fundus autofluorescence demonstrated mild hyperfluorescent lesions in both eyes. SD-OCT showed that the interdigitation zone was indistinct in both eyes, and the inner nuclear layer was slightly thinner. The amplitudes of the rod, cone, and 30-Hz flicker ERGs were severely reduced, and the implicit times were prolonged. The a- and b-waves of the bright-flash mixed rod-cone ERGs were also reduced. The dark-adapted oscillatory potentials were reduced. The amplitudes of the mfERGs were severely depressed except at the fovea in both eyes. CONCLUSIONS: These findings indicate that the RPE atrophy was wider and the rod dysfunction was more severe affected than that of previously reported MELAS cases with the m.3243A > G mutation.
PURPOSE: Mitochondrial encephalopathy with lactic acid and stroke-like episodes (MELAS) is caused by mutations in the mitochondrial DNA. Approximately 80% of MELAS patients have an A > G transition mutation at nucleotide pair 3243 in the mitochondrial DNA, m.3243A > G. There are also MELAS patients with a one-base deletion at nucleotide pair 3271 in the mitochondrial DNA, m.3271delT, but these cases are very rare. We report a case of MELAS with the m.3271delT and describe the retinal structure and electrophysiological alterations. METHODS: The retinal structure and function of a 37-year-old woman who was referred to our clinic for of nyctalopia were studied. Standard ophthalmological examinations including the medical history, measurements of the best-corrected visual acuity, intraocular pressures, and slit-lamp biomicroscopy, ophthalmoscopy, fluorescein angiography, fundus autofluorescence, spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (ERG), and multifocal electroretinography (mfERG) were performed. RESULTS: Fundus examination showed bilateral hypopigmentary changes of the retinal pigment epithelium which extended from the posterior pole to the equator. Fluorescein angiography showed patchy hyperfluorescence due to window defects at the atrophic areas. Fundus autofluorescence demonstrated mild hyperfluorescent lesions in both eyes. SD-OCT showed that the interdigitation zone was indistinct in both eyes, and the inner nuclear layer was slightly thinner. The amplitudes of the rod, cone, and 30-Hz flicker ERGs were severely reduced, and the implicit times were prolonged. The a- and b-waves of the bright-flash mixed rod-cone ERGs were also reduced. The dark-adapted oscillatory potentials were reduced. The amplitudes of the mfERGs were severely depressed except at the fovea in both eyes. CONCLUSIONS: These findings indicate that the RPE atrophy was wider and the rod dysfunction was more severe affected than that of previously reported MELAS cases with the m.3243A > G mutation.
Authors: Daphne L McCulloch; Michael F Marmor; Mitchell G Brigell; Ruth Hamilton; Graham E Holder; Radouil Tzekov; Michael Bach Journal: Doc Ophthalmol Date: 2014-12-14 Impact factor: 2.379
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