Article
Fundus autofluorescence in carriers for choroideremia
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Published: | September 22, 2004 |
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Outline
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Objective
Choroideremia is a rare X linked retinal degeneration caused by mutations in the REP-1 gene. Due to lyonization carriers show a variable funduscopical aspect. Histopathologic studies disclose diseased and normal areas with variable amounts of lipofuscin in the retinal pigment epithelium (RPE) (Syed et al. 2002).
Methods
In four carriers for choroideremia from independent families, a complete ophthalmologic examination was performed. In 2/4 carriers, psychophysical and electrophysical testing was also performed. Two families had moleculargenetically verified mutations. Fundus autofluorescence (AF) was recorded using a HRA (Heidelberg Retina Angiograph).
Results
All four carriers (aged 47, 51, 53, 60 years) had a good visual acuity, but complained about visual problems like photophobia and impaired vision in dim light. Electrophysiological and psychophysical testing revealed functional disturbances in rods and cones. Funduscopy showed RPE changes of variable intensity. In AF a very irregular pattern was seen, which was clearly different from the AF pattern seen in carriers for RP3 (Wegscheider et al., Graefe's Arch Ophth 2004). Besides reduced AF around the optic nerve head, corresponding to the peripapillary atrophy, the whole macular region revealed small areas of reduced AF besides spots of enhanced AF. The central perifoveal area covering 3-4° appeared more homogenous.
Conclusions
All four carriers showed a similar specific AF pattern, which was markedly different from the pattern seen in carriers for RP3. In the early stage, both diseases may have a relatively similar fundus appearance in hemizygotes. AF may therefore help to differentiate the two disease entities.