First Author: C.Plaza Laguardia SPAIN
Co Author(s): A. Mateos L. Monje M. Cuesta F. Costales E. Pertejo I. Garzo
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To further describe the findings in the unusual symptomatic CHM carrier state.
A wide study with fluorescein angiography, visual field, ERG, EOG and OCT-Angiography has been performed.
A 50-year-old woman presented with visual loss throughout the last year, as well as a molecular carrier state diagnosis of mutation c.161+1G>C in the CHM gene. Fundus examination showed atrophy of the RPE and choroid spreading to periphery and central retina, with large choroidal vessels on the naked sclera. Foveal structures were conserved in the right eye. A neovascular membrane was found in the left eye and treated with intravitreal ranibizumab. Fluorescein angiography demonstrated lack of filling of the choriocapillaris, with the right eye normal fovea showing hypofluorescence surrounded by the hyperfluorescence due to the window defect. Bilateral visual field defect with greater central impairment of the OS was detected. ERG showed markedly diminished amplitude of peripheral rings of both eyes. OCT-Angiography displayed areas of flow loss in the choriocapillaris and choroid.
Choroideremia is a rare retinal dystrophy, in which female carriers often demonstrate slight patchy defects of the RPE or peripheral pigmentary granularity. However, severe retinal damage is possible, even in carriers, likely due to unbalanced X-chromosome inactivation . The ERG should be normal in female carriers even with characteristic fundus changes. However, abnormal responses may be in carriers with a dark-adapted white flash, a dim blue flash or a flickering stimulus, there are no specific test results in carrier status. It is important to consider that in such patients, the response of the abnormal retinal pigment epithelium can develop a CNV. Fibrosis due to neovascularization has been reported in few cases. New techniques of retinal imaging such as OCT-Angiography are allowing the best characterization of this kind of dystrophies and its progression.