Purpose: Mutations in the ABCA4 gene are heterogeneous and somewhat ethnic specific and can result in autosomal recessive Stargardt disease (STGD1), cone or cone-rod dystrophy (CRD), and retinitis pigmentosa. The objective of this study was to determine the ABCA4 mutation detection rate and mutation spectrum in a cohort of Chinese patients with STGD1 or CRD and describe the clinical features of the patients with ABCA4 mutations. Methods: A total of 161 probands were recruited for genetic analysis; these included 96 patients diagnosed with STGD1 and 65 individuals with CRD. All probands underwent ophthalmic examinations. All coding exons and exon–intron boundaries of the ABCA4 gene were screened for mutations by PCR-based DNA sequencing, followed by analyses for pathogenicity by in silico programs. Results: We found at least two disease-causing ABCA4 alleles in 102 unrelated patients (63.4%), one disease-causing allele in 16 patients (9.9%), and no disease-causing allele in 43 affected individuals (26.7%), giving an overall mutation detection rate of 73.3% (118/161). In total, 136 disease-causing variants of the ABCA4 gene, including 85 novel ones, were identified. The identified mutations included 77 (57.0%) missense, 19 (14.1%) nonsense, 23 (17.0%) splicing effect, and 16 (11.9%) frameshift small insertion or deletion mutations. The most frequent mutation in this cohort was c.2424C>G p.Y808X, representing 4.7% of all screened alleles (15/322). Conclusions: The mutation spectrum of the ABCA4 gene in Chinese patients is quite different from that for Caucasian patients. The establishment of the mutation profile will facilitate ABCA4 screening and risk evaluation for Chinese patients with STGD1.

Purpose: Usher syndrome (USH) refers to a group of autosomal recessive disorders causing deafness and blindness. The objectives of this study were to determine the mutation spectrum in a cohort of Chinese patients with USH and to describe the clinical features of the patients with mutations. Methods: A total of 119 probands who were clinically diagnosed with USH were recruited for genetic analysis. All probands underwent ophthalmic examinations. A combination of molecular screening methods, including targeted next-generation sequencing, Sanger–DNA sequencing, and multiplex ligation probe amplification assay, was used to detect mutations. Results: We found biallelic mutations in 92 probands (77.3%), monoallelic mutations in 5 patients (4.2%), and 1 hemizygous mutation in 1 patient (0.8%), resulting in an overall mutation detection rate of 78.2%. Overall, 132 distinct disease-causing mutations involving seven USH (ABHD12, CDH23, GPR98, MYO7A, PCDH15, USH1C, and USH2A) genes; 5 other retinal degeneration genes (CHM, CNGA1, EYS, PDE6B, and TULP1); and 1 nonsyndromic hearing loss gene (MYO15A) were identified, and 78 were novel. Mutations of MYOA7 were responsible for 60% of USH1 families, followed by PCDH15 (20%) and USH1C (10%). Mutations of USH2A accounted for 67.7% of USH2 families, and mutation c.8559-2A>G was the most frequent one, accounting for 19.1% of the identified USH2A alleles. Conclusions: Our results confirm that the mutation spectrum for each USH gene in Chinese patients differs from those of other populations. The formation of the mutation profile for the Chinese population will enable a precise genetic diagnosis for USH patients in the future.

Background: Leber congenital amaurosis (LCA) and early onset severe retinal dystrophy (EOSRD) are clinically and genetically heterogeneous inherited retinal disorders that cause severe visual impairment in children. The objective of this study was to describe the mutation profile and phenotypic characteristics in Chinese patients with LCA or EOSRD.Methods: Retrospective consecutive case series (2010–2017) study was performed in 148 probands (91 with LCA and 57 with EOSRD). All patients underwent ophthalmic evaluation. Mutations were revealed using targeted next-generation sequencing, followed by Sanger DNA-sequencing and real-time quantitative PCR analysis.Results: We identified two diseasing-causing mutations in 88 unrelated patients, heterozygous autosomal dominant mutations in 11 probands and X-linked hemizygous mutations in 11 patients, for an overall mutation detection rate of 74.3% (110/148). We detected 158 different disease-causing mutations involving 14 LCA genes, 16 retinitis pigmentosa or cone-rod dystrophy genes and 3 syndromic retinal dystrophy genes. Of these 158 mutations, 98 were novel. The most common mutation was p.Q141X of AIPL1, with a gene-specific allele frequency of 60%. The first five most frequently mutated genes were AIPL1 (11.0%), RPGRIP1 (8.8%) and CEP290, GUCY2D and RPE65 (each 7.7%) in the patients with LCA and RPGR (12.3%), CRB1 (10.5%), RPE65 (10.5%), RDH12 (7.0%) and RP2 (5.3%) in the patients with EOSRD.Conclusions: Our results revealed that the mutation spectrum of patients with LCA differs from that of the patients with EOSRD and established the configuration of the mutation frequencies for each LCA gene in Chinese patients, thereby providing essential information for future genetic counselling and gene therapy.

Purpose: Mutations in the BEST1 gene can cause Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB). The aim of the current study was to establish the BEST1 mutation spectrum in Chinese patients with BVMD and ARB and to describe the phenotypic characteristics of patients carrying BEST1 mutations. Methods: A total of 37 probands with a clinical diagnosis of BVMD (17 patients) or ARB (20 patients) were recruited for genetic analysis; of these, only 5 probands had a family history. All probands underwent detailed ophthalmic examinations. All coding exons and exon-intron boundaries of the BEST1 gene were screened by PCR-based DNA sequencing. In silico programs were used to analyze the pathogenicity of all the variants. Genomic DNA rearrangements of the BEST1 gene were identified by real-time quantitative PCR (RQ-PCR). Results: For patients with BVMD, single heterozygous BEST1 mutations were identified in 13 patients and compound heterozygous mutations were found in 3 patients. For patients with ARB, biallelic mutations were found in 13 probands and single mutant alleles in six patients. Overall, 36 disease-causing variants (20 novel mutations) of the BEST1 gene were identified, including 28 (77.8%) missense, 3 (8.3%) nonsense, 4 (11.1%) splicing effect, and 1 (2.8%) frameshift small duplication mutations. Conclusions: The mutation spectrum of the BEST1 gene in Chinese patients differed from those of Caucasian patients. Mutations that cause ARB differ from those that cause BVMD. BEST1 screening is important for precise diagnosis of BVMD or ARB.

To investigate the role of microRNA-145 (miRNA-145) and microRNA-205 (miRNA-205) in proliferation and invasion of uveal melanoma (UM) cells. The expression level of miRNA-145 and miRNA-205 from samples of UM patients were determined by real-time polymerase chain reaction (RT-PCR). The growth and invasion inhibitory effects were observed by the transfection of UM cells with miRNA-145 and miRNA-205. Several epithelial-to-mesenchymal transition (EMT)-related proteins were screened by Western blotting. UM clinical samples from The Cancer Genome Atlas (TCGA) were applied to search for potential protein interaction. Pearson's correlation analysis was applied to estimate co-expression between genes. Dual-luciferase reporter assay was used to verify the binding sites on target protein for miRNA-145 and miRNA-205. The expression levels of miRNA-145 and miRNA-205 in the samples from patients with UM were significantly lower than those in the normal tissue samples. Significant growth and invasion inhibitory effects were observed in human UM cells with miRNA-145 and miRNA-205 overexpression. The miRNA-145 and miRNA-205 could decrease the expression level of cell division control protein 42 (CDC42). After database searching and sequence alignment, we identified that Neuropilin 1 (NRP1) had binding sites for both miRNA-145 and miRNA-205. The miRNA-145 and miRNA-205 can reduce the proliferation, migration and invasion of UM cells by targeting the mRNA of its upstream protein NRP1 to down-regulate the expression level of CDC42.