Gain of function in BEST1: photoreceptor changes and myopia in autosomal dominant vitreoretinochoroidopathy

PURPOSE: Autosomal dominant vitreoretinochoroidopathy (ADVIRC) is associated with gain-of-function in bestrophin-1 instead of loss-of-function or dominant-negative mechanisms in other bestrophinopathies. We aimed to characterize photoreceptor (PR) changes in ADVIRC compared to Best vitelliform macular dystrophy (BVMD) and controls. METHODS: A retrospective case series of 8 ADVIRC, 10 BVMD, and 10 control eyes was conducted. Outer segment and PR layer (OPL/ONL junction to RPE) thicknesses were measured on horizontal optical-coherence-tomography line scans at -2.5 (nasal) to +2.5 (temporal) mm from the fovea and compared using the Kruskal-Wallis H test and Mann-Whitney U test. RESULTS: Median age of ADVIRC, BVMD, and control patients was 51.0, 38.0, and 50.0 years, respectively, visual acuity (logMAR) was 0.20, 0.02, and 0.00; axial length was 24.7, 23.6, and 23.7 mm; and spherical refraction was -0.63, 0.00, and 0.00 diopters, respectively. The ADVIRC outer segment layer was significantly thinner than BVMD eyes at all locations from the fovea, and the ADVIRC PR layer was significantly thinner than BVMD and control eyes at perifoveal locations. Systematic review of published ADVIRC cases showed increased prevalence of myopia vs. hyperopia. CONCLUSION: This study found that gain-of-function in ADVIRC may cause increased prevalence of myopia, PR layer thinning, and outer segment shortening.