Autosomal recessive bestrophinopathy: new observations on the retinal phenotype - clinical and molecular report of an Italian family

Purpose: To describe the genotype and phenotype in a 9-year-old boy with bilateral retinopathy. Methods: The patient, his healthy (by history) nonconsanguineous parents and his sister were examined by best-corrected visual acuity, matrix frequency doubling technology, monocular static field analysis, fundus autofluorescence imaging, optical coherence tomography, Ganzfeld electroretinography (ERG), pattern ERG, multifocal ERG, electro-oculography and genotyping of the BEST1 gene. Results: The patient presented with an Arden ratio of 1.25, an unremarkable ERG and fluorescent yellow deposits distributed throughout the fundus suggestive of autosomal recessive bestrophinopathy (ARB). Genotyping revealed a homozygous nonsense mutation in BEST1 (p.R200X). The parents and the sister, who were heterozygous mutation carriers, presented with normal ophthalmological function. Conclusions: ARB is a rare retinal disorder. We contribute a novel patient report indicative of ARB, assessed by clinical examination and confirmed by genotyping of BEST1, to the short list of ARB cases in the literature.