Poster 4 Joaquin Castro Navarro

Advantages:

To show the clinical evolution of a child with a novel mutation in exon 6 of gene RDH12 (gene typically associated with Leber Congenital Amaurosis: LCA) and severe early-onset macular degeneration.

Methods:

An 8-year-old male with unremarkable ocular and systemic history who came to our department with a complaint of progressive decline in vision in his both eyes. Full clinical ophthalmological examination, including genetic study, was performed.

Effectiveness / Safety:

At first visit, Best Corrected Visual Acuity (BCVA) was 10/100 in both eyes. Anterior segment examination was unremarkable. Fundus eye examination revealed the presence of a bilateral and symmetric pattern of macular hyperpigmentation (of three disk diameters in size) which adopted a reticular configuration with patches of hypopigmentation between hyperpigmentated areas. No peripheral atrophy with bone spicule nor optic nerve atrophy were observed. Optical Coherence Tomography (Cirrus SD) showed an intense macular atrophy with severe disruption of complex pigment retinal epithelium-photoreceptors. Farnsworth Munsell 28-hue test revealed preserved colour vision. Visual field showed a central scotoma. Electeroretinogram recordings demonstrated a diminished but still preserved rod and cone function. Genetic study showed the following heterocigotic mutations: exon 6: c.806_810delCCCTG (NM_152443.2RefSeq), p.Ala269fs and exon 6: c.701G>A (NM_152443.2RefSeq), p.Arg234His.Two years later BCVA decreased to <10/100 and we observed progression of the macular atrophy.

Take home message:

A novel mutation in exon 6 of gene RDH12 (p.Ala269fs and p.Arg234His) can be associated, although extremely infrequently, with an early-onset form of severe retinal dystrophy affecting both rod and cone function (both partially preserved at first stages) and having a phenotype distinct from that resulting from mutations in other known LCA genes.