Abstract
Purpose:
Foveal sparing atrophy is a phenotypic feature in which macular atrophy surrounds the fovea for at least 180° and does not include the fovea in the atrophic lesion. This specific feature is observed in a subset of patients with Stargardt disease, the most common juvenile-onset macular dystrophy caused by mutations in the ABCA4 gene. Here, we provide clinical and genetic details of Stargardt disease patients with foveal sparing atrophy.
Methods:
Thirteen Stargardt patients with foveal sparing (19 eyes) were collected. We collected available clinical data of these patients, including medical history, ophthalmic examination, fundus photography, autofluorescence (AF) images, optical coherence tomography (OCT) images, electroretinography (ERG) and genetic testing for mutations in the ABCA4 gene.
Results:
The mean age of onset was 51.2 years. Eleven patients (85%) initially presented with loss of visual acuity, which deteriorated from 20/25 to 20/200 in approximately two decades. Normal foveal retinal layer structure was preserved in OCT examinations of most patients. AF images showed atrophic lesions starting in the parafoveal area that progress over time around the fovea, creating the ‘peninsula-like’ foveal sparing feature. The atrophy subsequently surrounded the fovea completely, followed by a degeneration of the whole fovea in some patients. Full-field electroretinography revealed normal photopic cone responses in most patients, but can be moderately to severely reduced. Sequence analysis of the 50 protein coding exons of ABCA4 revealed compound heterozygous mutations in three patients. The remaining patients carried heterozygous ABCA4 mutations.
Conclusions:
Foveal sparing in Stargardt’s dystrophy is especially present in patients with a late onset of the disease. The mechanisms by which the fovea is spared while the surrounding tissue atrophies remains unclear. Factors that stimulate preservation of the central fovea may play a role in the development of future therapeutic strategies.
Keywords: 494 degenerations/dystrophies •
585 macula/fovea