Abstract
Purpose:
To describe a phenotype with ABCA4- related retinal dystrophies without fundus abnormalities.
Methods:
From our database of 429 patients with ABCA4- related dystrophies, we selected 7 patients with 2 or more ABCA4- mutations and in whom no fundus abnormalities were found in ophthalmoscopy or fundus photographs at the initial visit. We evaluated also the history of the patient and the results of the visual acuity (VA), fundus autofluorescence (FAF) or fluorescein angiography (FA), full-field electroretinography (ffERG) and spectral-domain optical coherence tomography (SD-OCT). ABCA4-analysis was performed using microarray analysis and sequencing.
Results:
All selected 7 patients had an age of onset of ≤12 years. All patients were carriers of severe ABCA4-mutations. In 4 patients the VA was in five years decreased into 0.3 or less. In 4 patients were subtle foveal hyperautofluorescence seen on FAF or FA when there was no fundus abnormality present on photography or ophthalmoscopy. All patients had initial foveal atrophy. One patient showed foveal thickening of the external limiting membrane on SD-OCT. The ffERG in 3 patients revealed responses that were reduced in a cone-rod pattern. Four children were suspected of psychological problems. In 6 patients was a delay of at least one year in diagnose.
Conclusions:
The phenotype of ABCA4- related retinal dystrophies without fundus abnormalities are at the severe end of clinical appearance. It includes patients with an age of onset of ≤12 years. They have a rapid vision loss. Because of in the beginning are no fundus abnormalities found, some children are suspected of a conversion syndrome and had a delay in right diagnose. We want to make ophthalmologist alert on this kind of phenotype.
Keywords: 696 retinal degenerations: hereditary