RDH12 mutation and early-onset retinal degeneration

Purpose To show the clinical evolution of a child with RDH12 mutation (gene typically associated with Leber Congenital Amaurosis,LCA) and early-onset retinal degeneration Methods A 8-year-old male who came to our department with a complaint of progressive decline in vision in his both eyes. Full clinical ophthalmological examination, including Best Corrected Visual Acuity (BCVA), anterior and posterior segment examination, Optical Coherence Tomography (OCT), color vision test, visual field, electrorretinogram and genetic study, was performed. Results At first visit, BCVA was 10/100 in both eyes. Anterior segment examination was unremarkable. Fundus eye examination revealed a bilateral and symmetric pattern of macular hyperpigmentation (of three disk diameters in size)with reticular configuration and patches of hypopigmentation between hyperpigmentated areas. No peripheral atrophy with bone spicule nor optic nerve atrophy were observed. OCT showed an intense macular atrophy with severe disruption of complex pigment retinal epithelium-photoreceptors. Farnsworth Munsell 28-hue test revealed preserved color vision. Visual field showed a central scotoma. Electrorretinogram recordings demonstrated a still preserved rod and cone function. Genetic study revealed a compound heterocigotic mutation for RDH12 in exon 6 (p.Ala269fs and p.Arg234His). Two years later VA decreased to <10/100 and we observed progression of the macular damage. Conclusion RDH12 mutation can be associated, although extremely infrequently, with an early-onset form of severe retinal dystrophy affecting both rod and cone function (preserved at first stages) and having a phenotype distinct from that resulting from mutations in other known LCA genes.