Clinical, phenotypic and genetic characteristics of macula‐sparing stargardt disease

Abstract

Aims/Purpose: Fundus flavimaculatus and Stargardt's disease are monogenic but heterogeneous disease entities leading to loss of central vision in adolescence, caused by more than 490 mutations in the ABCA4 gene. We herein report the clinical, phenotypic and genetic characteristics of adult onset fovea sparing Stargardt's disease.Methods: Two Caucasian males in their 40s presenting with complaints of paracentral scotomata underwent complete ophthalmic exam, visual field testing, optical coherence tomography (OCT), fundus autofluorescence (FAF), fluorescein angiography (FA), electroretinography (ERG) and genetic testing.Results: Visual acuity was 20/20 in both patients with normal IOP. Anterior segments were unremarkable. Posterior segment examination revealed pigment mottling in the macula with ring‐shaped perifoveal chorioretinal atrophy and numerous white deposits in the mid‐periphery. Visual fields confirmed the paracentral ring scotomata. OCT demonstrated concentric perifoveal loss of outer retinal layers with foveal sparing simulating oedema. Extensive hyperautofluorescence in the area of chorioretinal atrophy was revealed by FAF. Full‐field ERG confirmed incomplete loss of cone bioelectrical activity with preserved morphology of the foveal peak and normal rod function. Genetic testing discovered several pathogenic mutations in both patients with shared ABCA4 c.5603A>T, p.(Asn1868Ile), a risk factor mutation. None of the mutations of our patients were previously reported in foveal sparing Stargardt's disease.Conclusions: The variant ABCA4 c.5603A>T, p.(Asn1868Ile) might be associated with foveal sparing Stargardt's disease. Further population studies are need to confirm this association.