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Purpose: To report novel BEST1 variants in six Chinese families with bestrophinopathies of two different inheritance modes and analyze the intrafamilial phenotypic diversity. Method: A total of 25 participants including 13 patients and 12 healthy family members from 6 Chinese families with bestrophinopathies were available for genetic and clinical analysis. All of the patients were subjected to comprehensive ophthalmic evaluations and exome sequencing was performed on the probands to detect the causative variants. The pathogenicity of gene variants was predicted using silico analysis and evaluated according to ACMG guidelines. All (likely) pathogenic variants were determined by Sanger sequencing and co‐segregation analyses were performed on available family members. The relevant original literature previously reported was retrieved to explore the relationship between BEST1‐related gene variants and clinical features. Results: In the 6 families, 3 families (10 patients) were assigned as autosomal dominant bestrophinopathies (VMD) and 3 families (3 patients) were assigned as Autosomal recessive Bestrophinopathies (ARB). A total of 9 variants on the BEST1 gene were identified, containing 7 missense variants, 1 nonsense variant, and 1 frameshift variant, respectively, of which 3 variants c.88A > G (p.Lys30Glu), c.764G > A (p.Arg255Gln) and c.233dupT (p.Ser79Phefs*153) were novel variants. Three families with ARB were detected with heterozygous variants on the BEST1 gene.2 families (8 patients) with BVMD showed markedly irregular dominant inheritance, and the severity of macular lesions varies greatly among individuals of the same family. Among them, the probands showed typical vitelliform lesions in the macula, while the other six patients had no visible signs of the disease by fundus photography (ophthalmoscopy) and minor lesions could be detected on OCT in two patients, the continuity of the ellipsoidal band was interrupted with the chimeric band. The phenotypes of the patients in the three ARB families ranged from typical/atypical vitelliform lesions to extensive extramacular deposits (peripheral spots). Conclusion: This study provided evidence that the phenotype of BVMD manifested irregular dominant inheritance, with patients carrying a pathogenic heterozygous variant of BEST1 to develop obvious intrafamilial phenotypic diversity, and the patients who harbor two pathogenic alleles showed recessive inheritance bestrophinopathies with distinct phenotypic diversity. Our study also emphasized the importance of comprehensive genetic analysis in patients with bestrophinopathies, and in such challenging families with distinct intrafamilial phenotypic diversity, it shall provide novel insights into phenotypic assessments of bestrophinopathies, and contribute to better diagnosis, prognosis, and treatment for these patients. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to describe the genetic and clinical characteristics of Chinese patients with autosomal recessive bestrophinopathy (ARB). Methods: This study presents a retrospective observational case series. Twenty‐one ARB patients and 25 clinically healthy family members were recruited. The coding regions and adjacent intronic regions of BEST1 were analysed via Sanger sequencing. Clinical examinations, including ultrasound biomicroscopy, A‐scan, optical coherence tomography, fundus autofluorescence, fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA) and visual electrophysiology, were reviewed. Results: Six novel mutations (c.380C>T, p.T127M; c.397A>G, p.N133D; c.500A>G, p.E167G; c.817G>A, p.V273M; c.174_176del, p.Q58del; and c.950_955del, p.S318_L319) and 8 previously reported mutations were identified. The p.R255W mutation had the highest frequency in our cohort. Twenty patients had serous retinal detachment with multifocal subretinal vitelliform deposits in the posterior poles. One patient exhibited chorioretinal atrophy. FFA revealed peripheral vascular leakage in 10 patients, and ICGA revealed hyperfluorescent spots in 8 patients. Visual electrophysiology was abnormal in all patients. Fifteen patients with angle closure (AC) or angle‐closure glaucoma (ACG) had shallower anterior chambers and shorter axial lengths than the patients with open angle, contributing to their risk of developing AC/ACG. One patient developed AC during the 7‐year follow‐up period. The misdiagnosis and missed rates were 35.3% and 58.8%, respectively. Conclusion: The six novel mutations and high frequency of p.R255W suggest ethnical differences in the BEST1 mutation spectrum among Chinese patients. BEST1 gene screening and detailed clinical examinations help establishing a diagnosis of ARB. Clinical evaluations of the risk of developing AC/ACG are recommended for ARB patients. [ABSTRACT FROM AUTHOR]

Purpose To determine the spectrum of BEST1 mutations and to study the phenotype in Slovenian families with Best vitelliform macular dystrophy ( BVMD) to identify genotype-phenotype correlations. Methods Twenty patients from five families underwent the ophthalmological examination including electrooculogram ( EOG; N = 17), fundus autofluorescence imaging ( N = 16) and optical coherence tomography ( N = 14). Mutational screening was performed by direct DNA sequencing of the BEST1 gene. Results Mutation c.43G>C (p.Gly15Arg) was detected in three patients from family M presenting with different clinical stages of Best disease. Mutation c.313G>C (p.Arg105Gly) was found in families K, ST, S, B and was associated with incomplete clinical penetrance and variable retinal changes, including extramacular and multifocal lesions. In three patients from family K, an atypical form of BVMD was observed; there were additional peripheral lesions outside of the vascular arcades in addition to the typical macular lesions. Multiple alterations between the vitelliruptive and pseudohypopyon stages over a period of 11 years were seen in one patient. Conclusion Two previously unreported disease-associated variants in the BEST1 gene (p.Gly15Arg and p.Arg105Gly) were found in Slovenian patients with Best disease. Our data expand the mutation spectrum of the BEST1 gene and further support the broad phenotypic variability observed clinically and with optical coherence tomography (OCT) and AF imaging. [ABSTRACT FROM AUTHOR]