New Evidence on BEST1 Genetic Variant Identified in a Patient with Best Vitelliform Macular Dystrophy Phenotype

Best Disease (BD), also known as Best Vitelliform Macular Dystrophy (BVMD), represents an inherited autosomal dominant macular dystrophy with a juvenile age of onset [1]. It is a phenotypically heterogeneous, bilateral condition that affects the retina and Retinal Pigment Epithelium (RPE) caused by pathogenic variants in the BEST1 gene located on chromosome 11q12-13 [2,3]. Typical fundus findings in BD are egg yolk-like, round or oval, lesions seen in the macula, and affected eyes may demonstrate various clinical stages, ranging from the previtelliform stage to Choroidal Neovascularization (CNV) [4]. The macular appearance in all stages is deceptive, as most patients maintain relatively good visual acuity throughout the course of the disease. Patients commonly experience visual compromise in early adulthood, although the age of onset can range from childhood to late adulthood [3] and most patients with BD maintain good vision in at least one eye. The presence of subretinal fluid or CNV has been associated with a poorer visual prognosis [4]. In this case report, we describe a patient with clinical features suggestive of Best disease. We discuss the differential diagnosis and we present the multimodal imaging of the retina used for both the diagnosis and follow up. We also report a genetic study that demonstrates more evidence on a novel genetic variant in the BEST1 gene. The same genetic mutation has been recently reported as a novel variant in a single patient with BVMD [5].