Fundus Autofluorescence in Carriers of Choroideremia and Correlation with Electrophysiologic and Psychophysical Data

Abstract

To describe fundus autofluorescence (FAF) in carriers of choroideremia (CHM), and to compare FAF findings with ophthalmoscopy and electrophysiologic and psychophysical data. Prospective, observational case series and systematic review. Six unrelated carriers of CHM. Clinical examination included a comprehensive ophthalmic examination, fundus photography, FAF, kinetic perimetry, 2-color threshold perimetry (2CTP), full-field electroretinography (ERG), and multifocal ERG (mfERG). All 6 carriers (33-60 years of age) were screened for mutations in the coding region of Rab Escort Protein 1 gene (REP1) including close flanking intronic sequence and deletions within 2160 bp of 5' untranslated sequence. Intensity and distribution of FAF, rod sensitivity loss, cone sensitivity loss in 2CTP, amplitude and latency in full-field ERG, amplitude in mfERG, and correlation of all 3 parameters. Mutations in the coding region of REP1 were identified in 3 of 6 carriers. All 6 carriers had good visual acuity. Three carriers complained of photophobia and 1 of impaired vision in dim light. Ophthalmoscopy revealed peripapillary atrophy and retinal pigment epithelium (RPE) mottling mainly in the macular region, and additional RPE clumping and flecks of atrophy in the periphery. A very irregular pattern of low- and high-density FAF speckles was seen. Low-density FAF surrounding the optic nerve head corresponded with the peripapillary atrophy. In areas of major FAF changes, mfERG was deteriorated. The 2CTP images revealed functional disturbances in rods and cones. No general pattern was observed. On MfERG, reduced amplitudes in areas with normal cone sensitivity in 2CTP were seen. All 6 carriers of CHM showed a characteristic FAF pattern that can guide mutation analysis. Even when other functional testing is inconspicuous, FAF is a rapid, noninvasive indicator. The authors have no proprietary or commercial interest in any of the materials discussed in this article.