RESUMEN
Bestrophinopathies are a group of inherited macular dystrophies caused by BEST1 gene mutations including Best vitelliform macular dystrophy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy and autosomal recessive bestrophinopathy.The main pathological mechanism of bestrophinopathies is that the primary lesion located in the retinal pigment epithelium will affect the photoreceptor cells.The mutations in BEST1 gene not only result in macular lesions, but also potentially affect the development of eyeball, and even cause serious complications such as angle-closure glaucoma and choroidal neovascularization.It is highly heritable and clinically heterogeneous.The same pathogenic mutation site in BEST1 can lead to different clinical phenotypes, which are complex and varied and can bring great confusion to clinicians, causing misdiagnosis and missed diagnosis the disease.This review aimed to summarize and analyze the clinical manifestations of bestrophinopathies and the research progress in BEST1 gene mutations, so as to improve the understanding of clinicians toward this kind of disease and provide reference for clinical practice and future research.
RESUMEN
Objective:To report the BEST1 gene mutations and clinical phenotypes in two pedigrees with Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB). Methods:A retrospective clinical study. From November 2019 to March 2021, in the Department of Ophthalmology of The First Affiliated Hospital of Zhengzhou University, the BVMD family (4 patients and 6 family members) and the ARB family (2 patients, 2 family members), a total of 6 patients and 8 normal family members were included in the study. Detailed medical history was obtained; best corrected visual acuity, fundus color photography, electrophysiology, optical coherence tomography and fundus autofluorescence examination were performed. The clinical characteristics for all patients in the two families were analyzed. Three milliliter peripheral venous blood of all participants in the family was collected, and the whole genomic DNA was extracted with gene sequencing using next-generation sequencing technology based on targeted capture. Compared with the database to identify the pathogenicity mutation sites, suspected pathogenic mutation sites were selected, then mutations in other members in the family was assayed by Sanger sequencing.Results:In family 1, the proband was demonstrated as typical BVMD, other patients were multifocal vitelliform macular dystrophy. The DNA sequencing result showed that all the 4 patients carried heterozygous missense mutations in exon 3 of BEST1 gene: c.240C>G (p.F80L) (M1) and 2 members carried this mutation, but without clinical phenotype. M1 was a likely-pathogenic mutation reported for the first time. In family 2, the proband and the other patient were diagnosed as ARB. The DNA result showed that the 2 patients carried heterozygous missense mutations in exon 5 and exon 2 of BEST1 gene: c.584C>T (p.A195V) (M2)、c.139C>A (p.R47S) (M3), and a heterozygous frameshift mutation in exon 3 of BEST1 gene: c.235dupT (p.S79Ffs*153) (M4). M2 was a pathogenic mutation reported previously. M3 variant was of undetermined significance. M4 was a first reported pathogenic mutation. Conclusions:The BEST1 gene mutation is the main cause of BVMD and ARB. Different mutation sites have different clinical phenotypes. BVMD and ARB have genetic and clinical heterogeneity.