Detection of Novel BEST1 Variations in Autosomal Recessive Bestrophinopathy Using Third-generation Sequencing.

OBJECTIVE: Autosomal recessive bestrophinopathy (ARB), a retinal degenerative disease, is characterized by central visual loss, yellowish multifocal diffuse subretinal deposits, and a dramatic decrease in the light peak on electrooculogram. The potential pathogenic mechanism involves mutations in the BEST1 gene, which encodes Ca2+-activated Cl- channels in the retinal pigment epithelium (RPE), resulting in degeneration of RPE and photoreceptor. In this study, the complete clinical characteristics of two Chinese ARB families were summarized. METHODS: Pacific Biosciences (PacBio) single-molecule real-time (SMRT) sequencing was performed on the probands to screen for disease-causing gene mutations, and Sanger sequencing was applied to validate variants in the patients and their family members. RESULTS: Two novel mutations, c.202T>C (chr11:61722628, p.Y68H) and c.867+97G>A, in the BEST1 gene were identified in the two Chinese ARB families. The novel missense mutation BEST1 c.202T>C (p.Y68H) resulted in the substitution of tyrosine with histidine in the N-terminal region of transmembrane domain 2 of bestrophin-1. Another novel variant, BEST1 c.867+97G>A (chr11:61725867), located in intron 7, might be considered a regulatory variant that changes allele-specific binding affinity based on motifs of important transcriptional regulators. CONCLUSION: Our findings represent the first use of third-generation sequencing (TGS) to identify novel BEST1 mutations in patients with ARB, indicating that TGS can be a more accurate and efficient tool for identifying mutations in specific genes. The novel variants identified further broaden the mutation spectrum of BEST1 in the Chinese population.

ELL associated factor 2 is a potential diagnostic and prognostic indicator: evidence from the in silico and in vitro experiments.

Due to the lack of sensitive biomarkers, cancer disease kill 9.6 million individuals each year around the globe. The present study aimed to explore the association between ELL Associated Factor 2 (EAF2) expression and its diagnostic and prognostic landscape across different human cancers using an in silico and in vitro approach. To achieve the defined goals of this study, we used the following online sources: UALCAN, KM plotter, TNMplot, cBioPortal, STRING, DAVID, MuTarget, Cytoscape, and CTD. In addition to this, we also used additional The Cancer Genome Atlas (TCGA) datasets via TIMER2, GENT2, and GEPIA to confirm the expression of EAF2 on additional cohorts. Finally, we performed RNA sequencing (RNA-seq) and targeted bisulfite sequencing (bisulfite-seq) techniques-based analysis using A549, ABC-1, EBC-1, LK-2 lung cancer cell lines, and MRC-9 normal control lung cell line for further validation of the results. On balance, EAF2 was elevated in 19 types of human cancers and its up-regulation was significantly correlated with shorter overall survival (OS), relapse-free survival (RFS), and metastasis in Liver Hepatocellular Carcinoma (LIHC) and Lung Squamous Cell Carcinoma (LUSC) patients. We further evaluated that EAF2 expression was also elevated across LIHC and LUSC patients belonging to different clinicopathological features. Through pathway analysis, EAF2 associations were observed with four important pathways. Moreover, some worth noticing correlations were also documented between EAF2 expression and its promoter methylation level, genetic alterations, other mutant genes, tumor purity, and different immune cells infiltration. The higher EAF2 expression contributes significantly to the tumorigenesis and metastasis of LIHC and LUSC. Therefore, it can be used as a common biomarker in these cancers.