Abstract
Purpose: :
To study macular structure and function in patients with mutations in the BEST1 gene.
Methods: :
The coding sequences of the BEST1 gene were bidirectionally sequenced in 6 patients from 4 families with bilateral vitelliform maculopathy. Adaptive Optics Scanning Laser Ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography (SDOCT) images were compared with normal subjects. Fundus autofluorescence (AF), visual acuity (VA), kinetic and static perimetry, electro-oculography (EOG), full-field (ffERG) and multifocal electroretinography (mfERG) were measured.
Results: :
Heterozygous mutations in BEST1 were present in all patients (Patient 1, Glu292Lys; Patient 2, Arg218His; Patients 3 and 4, Glu300Lys; Patients 5 and 6, Val9Ala). VA ranged from 20/20-20/125. Vitelliform subretinal deposits were present in all patients; retinal pigment epithelium (RPE) atrophy was present in at least 1 eye of all but the youngest patient. Arden ratios were reduced, ffERG amplitudes and timing were normal and mfERG amplitudes were reduced with delayed timing in the affected areas. AF was increased centrally in all patients; some showed reduced AF within the hyperAF lesion consistent with RPE atrophy. 4 of 6 patients maintained foveal fixation while fixation was eccentric in 2 patients. VA was best in those without subretinal fluid, but was 20/25 in the presence of subretinal fluid where hyperreflective outer segments were observed adjacent to the fovea. Patients with reduced VA showed subretinal or subRPE fluid and loss of the outer segment layer. If cones were present inside the vitelliform lesions, they were generally weakly reflective and of low density, except in two patients who had discrete, highly reflective, contiguous patches of cones, some with normal spacing. Cones outside lesions were generally contiguous and close packed, but cone density was decreased where there was either increased AF or subretinal fluid. Cones were most normal at the borders of macular lesions without subretinal fluid and where AF was most normal.
Conclusions: :
AOSLO showed well-preserved cones outside regions with AF deposits, subretinal fluid or photoreceptor/RPE atrophy in patients with BEST1 mutations, suggesting AF abnormalities and subretinal fluid are associated with cone loss.
Keywords: retinal degenerations: hereditary • imaging/image analysis: clinical • photoreceptors