Mutational spectrum in a Chinese cohort with congenital cataracts.

BACKGROUND: To identify the mutational spectrum in a Chinese cohort with congenital cataracts. METHODS: Probands (n = 164) with congenital cataracts and their affected or unaffected available family members were recruited for clinical examinations and panel-based next-generation sequencing, then classified into a cohort for further mutational analysis. RESULTS: After recruitment (n = 442; 228 males and 214 females), 49.32% (218/442) of subjects received a clinical diagnosis of congenital cataracts, and 56.88% (124/218) of patients received a molecular diagnosis. Eighty-four distinct variants distributed among 43 different genes, including 42 previously reported variants and 42 novel variants, were detected, and 49 gene variants were causally associated with patient phenotypes; 27.37% of variants (23/84) were commonly detected in PAX6, GJA8 and CRYGD, and the three genes covered 33.06% of cases (41/124) with molecular diagnosis. The majority of genes were classified as genes involved in nonsyndromic congenital cataracts (19/43, 44.19%) and were responsible for 56.45% of cases (70/124). The majority of functional and nucleotide changes were missense variants (53/84, 63.10%) and substitution variants (74/84, 88.10%), respectively. Nine de novo variants were identified. CONCLUSION: This study provides a reference for individualized genetic counseling and further extends the mutational spectrum of congenital cataracts.

Clinical and Genetic Analysis of Retinitis Pigmentosa with Primary Angle Closure Glaucoma in the Chinese Population.

PURPOSE: Retinitis pigmentosa (RP) constitutes a class of common inherited retinal dystrophies. Patients with RP and comorbid primary angle-closure glaucoma (PACG) have been described, but the relationship between the diseases remains unclear. This study investigated the clinical and genetic characteristics of Chinese patients with RP and comorbid PACG. METHODS: Of 1356 patients with RP, we analyzed the genetic features of 39 RP patients with PACG using next-generation sequencing and reviewed their clinical characteristics. RESULTS: In total, 18 patients with acute PACG and 21 patients with chronic PACG were included in this study; their age at examination was 50.54 ± 12.99 years (range, 25.0-71.0 years), and their age at PACG onset was 46.04 ± 14.50 years (range, 24.9-68.0 years). Additionally, the mean lens thickness (LT) was 4.49 ± 0.44 µm, and the mean axial length (AL) was 22.63 ± 1.17 mm. Notably, the prevalence of PACG in patients with RP was 2.88%; this was higher than the prevalence in the general population. This could be explained by nanophthalmos, thickened lentis, ectopia lentis, or zonular insufficiency. Furthermore, patients with a shorter AL, a greater LT, iridociliary cysts, or nanophthalmos exhibited earlier development of PACG. Overall, 30 disease-causing variants spanning 17 genes were identified in 56.41% of the patients, and PRPH2 was the most common mutation gene. CONCLUSIONS: Our findings revealed that there is a strong association between RP and PACG. Furthermore, intraocular pressure (IOP) should be measured in patients with RP to protect them from the aggravated damage of an elevated IOP.

Nobiletin protects retinal ganglion cells in models of ocular hypertension in vivo and hypoxia in vitro.

Glaucoma, a common cause of blindness, is characterized by the progressive loss of retinal ganglion cells (RGCs). Growing evidence suggests that nobiletin (NOB) is a promising neuroprotective drug; however, its effects on glaucomatous neurodegeneration remain unknown. Using rat models of microbead occlusion in vivo and primary RGCs model of hypoxia in vitro, we first demonstrate that NOB reduces RGC apoptosis by a TUNEL assay, Hoechst 33342 staining and FluoroGold (FG) retrograde labeling. This effect does not depend on intraocular pressure (IOP) lowering. Additionally, NOB partially restored the functional and structural damage of inner retinas, attenuated Müller glial activation and oxidative stress caused by ocular hypertension. At 2 weeks after IOP elevation, NOB further enhanced Nrf2/HO-1 pathway in RGCs to withstand the cumulative damage of ocular hypertension. With the administration of HO-1 inhibitor tin-protoporphyrin IX (SnPP), the protective effect of NOB was attenuated. Overall, these results indicate that NOB exerts an outstanding neuroprotective effect on RGCs of glaucomatous neurodegeneration. Besides, interventions to enhance activation of Nrf2/HO-1 pathway can slow the loss of RGCs and are viable therapies for glaucoma.

Peripheral benzodiazepine receptor TSPO needs to be reconsidered before using as a drug target for a pigmentary disorder.

The peripheral benzodiazepine receptor (TSPO/PBR) is highly conserved among different species but with perplexing biochemical functions. Multiple ligands of TSPO show commendable regulatory activities in lots of biological functions, such as neuro-protection, cholesterol transport, and so on. These researches support that TSPO may be a potential target for disease treatment and drug development. Previous studies have shown that its ligands benzodiazepines show a satisfactory effect on melanogenic promotion. However, the potential application of TSPO in drug development for pigmentary disorder needs further investigation. In this study, we confirmed the melanogenesis induction of TSPO ligand, Ro5-4864 in mouse melanoma cell lines, human skin tissue, and zebrafish embryos by inducing melanin synthesis and melanosome transport. Molecular genetics and pharmacological studies showed that TSPO deficiency did not affect melanin production in B16F10 cells and zebrafish embryos, nor did it affect the melanin promotion effect of Ro5-4864. Whether or not TSPO exists, the expression of lots of melanogenesis-related proteins, such as TYR, TRP-1, DCT, Mlph, and Rab27 was upregulated with the Ro5-4864 administration. These results indicated that Ro5-4864 induces melanogenesis in a TSPO-independent manner, which is inconsistent with previous research. This research is a reminder that we need to be very careful during target validation in drug development.

Mutation Analysis of the RPGR Gene in a Chinese Cohort.

Purpose: The purpose of this study was to investigate the clinical and genetic characteristics of the retinitis pigmentosa GTPase regulatory factor gene (RPGR) in a Chinese cohort. Methods: A retrospective analysis was performed on 80 subjects with RPGR-retinal dystrophy (RPGR-RD) for detailed genetic and clinical characterization. The panel-based next-generation sequencing of 792 causative genes involved in common genetic eye diseases was conducted in all individuals, followed by clinical variant interpretation. Information, including age, sex, geographic distribution, family history, consanguineous marriage, age at symptom onset, disease duration, best corrected visual acuity (BCVA), and complete ophthalmologic examination results, was collected. Results: This cohort (41 men and 39 women) included 26 families (26 probands and their available family members) and 13 sporadic cases. The average age of these participants was 36.35 ± 17.68 years, and the majority of the families were from eastern China (28 families, 71.79%). The average duration of disease in the probands was 22.68 ± 15.80 years. In addition, the average BCVA values of the right and left eyes in the probands were 0.96 ± 0.77 and 1.00 ± 0.77, respectively. A total of 34 RPGR variants were identified, including 6 reported variants and 28 novel variants. Among these variants, NM_001034853.1: c.2899_2902delGAAG and c.2744_2745ins24 were considered de novo variants. The majority of the RPGR variants were classified as likely pathogenic, accounting for 70.59% of the variants (24 variants). The most common nucleotide and amino acid changes identified in this study were deletions (16 variants, 45.06%) and frameshifts (17 variants, 50.00%), respectively. Genetic analysis revealed that these RPGR variants were distributed in 10 different subregions of RPGR, and 70.59% of the RPGR variants (24 variants) were located in exon 15. Four RPGR variants, NM_001034853.1: c.2405_2406delAG, c.1345C > T, c.2218G > T and c.2236_2237delGA, occurred at a very high frequency of 28.21% (11 families) among 39 unrelated families. Conclusion: This study expands the known mutational spectrum of RPGR, and we provide a new reference for the genetic diagnosis of RPGR variants.

Regulation of mitophagy by metformin improves the structure and function of retinal ganglion cells following excitotoxicity-induced retinal injury.

Excitotoxicity-induced retinal neuronal death is characterized by the progressive retinal ganglion cell (RGC) apoptosis. Strategies are needed to reduce neurodegeneration. Recent investigations have indicated the potential effects of metformin on multiple systems, especially in the networks. However, it also remains unclear whether mitophagy contributes to the neuroprotective effect of metformin on the retina. In this study, excitotoxicity-induced retinal injury models were constructed. In vitro, R28 cells were treated with calcium ionophore and metformin/phosphate-buffer saline (PBS). Cell viability, lactate dehydrogenase release, and the cellular apoptosis rate were assessed. In vivo, rats received intravitreal injection of N-methyl-D-aspartate and metformin/PBS. Comprehensive examinations including retrograde fluorescent gold labelling, Nissl's staining, full-field electroretinography, photopic negative response, optic coherence tomography and retinal imaging, transmission electron microscopy, western blotting, and quantitative polymerase chain reaction were conducted during the observation period. The viability of R28 cells was significantly increased in the metformin-treated group compared with the negative control group, while, the release of lactate dehydrogenase and R28 cell apoptosis showed a significant decrease. In vivo, metformin treatment significantly increased the number of surviving RGCs, the b/NR wave amplitude and the thickness of the inner retina but had no obvious adverse effects on the fundus. In the metformin-treated group, the morphology and number of mitochondria were better preserved, as observed for RGCs; mitochondrial autophagosomes were located in RGCs, as indicated by transmission electron microscopy; and the expression of mitophagy-related genes and proteins presented was significant regulated. These data indicated that the regulation of mitophagy by metformin improved the structure and function of RGCs.

Genotypic spectrum and phenotype correlations of EYS-associated disease in a Chinese cohort.

BACKGROUND: To date, certain efforts have been made to investigate the clinical and genetic characteristics of patients with EYS mutations. However, data for Chinese patients are limited. OBJECTIVES: To perform a detailed phenotyping and genetic characterization of 55 Chinese patients with EYS-RD, and to identify risk factors for these clinical data. METHODS: A total of 55 patients with EYS-RD were recruited. Best-corrected visual acuity (BCVA), patient age, age at symptom onset, disease duration, and genetic information were collected. RESULTS: Thirty-six novel variants, three hot mutations of EYS (30.3%, c.6416G>A, c.6557G>A, c.7492G>C) and one hot region (49.06%, Laminin G domains) were identified. In all, 36.84% of the mutations occurred at base G site, and majority of mutations (56.56%) were missense. Late-truncating mutations are significantly more prevalent (41.30%). The mean age of onset was 15.65 ± 14.67 years old; it had no significant correlation with genotype. The average BCVA was 0.73 ± 0.93 LogMAR, and 61.8% of eyes had a BCVA better than 0.52 logMAR. BCVA was positively correlated with disease duration time. The mean MD was 23.18 ± 7.34 dB, MD showed a significant correlation with genotype and age. Cataract was present in 56.45% of patients, and 42.59% of patients showed an absence of pigmentation in the retina. Cataract and hyperpigmentation both showed a significant correlation with age. CONCLUSIONS: EYS-RD is associated with a moderate phenotype with onset around adolescence, but great variability. Our study largely enhances the current knowledge of phenotypic and genotypic characteristics of EYS-RD, which could pave the way for better management of these patients.

Frequency and phenotypic characteristics of RPE65 mutations in the Chinese population.

BACKGROUND: The retinoid isomerohydrolase RPE65 has received considerable attention worldwide since a successful clinical gene therapy was approved in 2017 as the first treatment for vision loss associated with RPE65-mediated inherited retinal disease. Identifying patients with RPE65 mutations is a prerequisite to assessing the patients' eligibility to receive RPE65-targeted gene therapies, and it is necessary to identify individuals who are most likely to benefit from gene therapies. This study aimed to investigate the RPE65 mutations frequency in the Chinese population and to determine the genetic and clinical characteristics of these patients. RESULTS: Only 20 patients with RPE65 mutations were identified, and RPE65 mutations were determined to be the 14th most common among all patients with genetic diagnoses. Ten novel variants and two hotspots associated with FAP were identified. A literature review revealed that a total of 57 patients of Chinese origin were identified with pathogenic mutations in the RPE65 gene. The mean best Snellen corrected visual acuity was worse (mean 1.3 ± 1.3 LogMAR) in patients older than 20 years old than in those younger than 15 years old (0.68 ± 0.92 LogMAR). Bone spicule-like pigment deposits (BSLPs) were observed in six patients; they were older than those without BSLP and those with white-yellow dots. Genotype-phenotype analysis revealed that truncating variants seem to lead to a more severe clinical presentation, while best corrected visual acuity testing and fundus changes did not correlate with specific RPE65 variants or mutation types. CONCLUSIONS: This study provides a detailed clinical-genetic assessment of patients with RPE65 mutations of Chinese origin. These results may help to elucidate RPE65 mutations in the Chinese population and may facilitate genetic counseling and the implementation of gene therapy in China.

Low-dose IL-2 therapy limits the reduction in absolute numbers of circulating regulatory T cells in rheumatoid arthritis.

BACKGROUND: Circulating regulatory T cells (Tregs) are responsible for mediating immune tolerance and maintaining immunological homeostasis. Decreases in Tregs may be involved in the onset of rheumatoid arthritis (RA). Low-dose interleukin-2 (IL-2) has been considered for the treatment of inflammatory diseases mediated by T cells. This study focused on the status of circulating CD4+T subsets and the clinical feasibility of IL-2 therapies in patients with RA. METHODS: The subjects included 888 patients with RA and 100 healthy controls (HCs); 233 RA patients received IL-2 treatment with 0.5 million international units (MIU)/day from days 1 through 5. The demographic features, disease activity, and levels of CD4+T cells measured by modified flow cytometry were collected in all RA patients before and after treatment. RESULTS: RA patients had lower absolute Treg counts (but not Th17) compared with HCs, which was associated with disease activity; previously treated RA patients had the fewest circulating Tregs (p < 0.05). Patients treated with low-dose IL-2 had a three-fold increase in absolute anti-inflammatory Treg counts, as well as a two-fold increase in the other CD4+T subsets. Moreover, post-treatment levels of markers of disease activity in RA patients treated with IL-2 were significantly lower than the baseline values (p < 0.001), with no apparent side effects. CONCLUSION: Decreased absolute counts of circulating CD4+T lymphocyte subsets were observed in patients with RA. Circulating Tregs, which mediate immune tolerance, may be involved in the pathogenesis and progression of RA; however, this was ameliorated by low-dose IL-2, without obvious side effects. PLAIN LANGUAGE SUMMARY: Low-dose IL-2 treatment for rheumatoid arthritis • Circulating Tregs may be involved in the pathogenesis and progression of RA.• The absolute count of Tregs was significantly correlated with disease activity measures.• Low-dose IL-2 was able to effectively expade Tregs and help for RA patients' symptoms remission without evaluated side effects.

Effects of cigarette smoke on the aggravation of ovalbumin-induced asthma and the expressions of TRPA1 and tight junctions in mice.

The occurrence of asthma is closely related to environmental factors such as cigarette smoke (CS), one of the common risk factors. Environmental stimuli have the potential to activate transient receptor potential ankyrin 1 (TRPA1) and cause or aggravate asthma. The destruction of tight junctions (TJs) between airway epithelial cells by environmental stimuli in asthma has been researched. It is worth exploring whether CS can injury TJs and aggravate asthma by activating TRPA1. The objective of this study was to investigate the aggravation of CS on ovalbumin (OVA)-induced asthma related phenotypes and TJs expression in mice, and to explore the relationship between TRPA1 and the expression of TJs protein. Female wild type (WT) C57BL/6 mice, induced by OVA, CS and OVA plus CS (OVA + CS) respectively, were used to establish a 42-day asthma model, and mice with TRPA1 knockout (TRPA1-/-) were treated in the same way. This study detected the number of inflammatory cells in peripheral blood and bronchoalveolar lavage fluid (BALF), the levels of IL-4, IL-5, IL-13 in BALF, enhanced pause (Penh) of lung function, pathological changes and the gene and protein expressions of TRPA1 and TJs (including ZO-1, Occludin and Claudin-2) in lung tissues. Compared with normal saline (NS) group, WT mice in the OVA group and OVA + CS group were significantly higher in asthma related phenotypes. The WT-OVA + CS group also showed higher Penh value, levels of IL-5 and IL-13 in BALF and lung tissue injury scores when compared with the WT-OVA group and WT-CS group. However, WT-OVA + CS group mice had significantly larger number of neutrophils in BALF than the WT-OVA group, and had larger number of eosinophils in peripheral blood and higher levels of IL-4 in BALF than the WT-CS group. Meanwhile, compared with the WT-NS group, the expressions of TRPA1 and Claudin-2 in lung tissues increased in other three groups while their expressions of ZO-1 and Occludin decreased, among which, the WT-OVA + CS group showed more remarkable changes. Compared with the WT-OVA + CS group, mice in the TRPA1-/--OVA + CS showed a significant decrease in the number of inflammatory cells, levels of IL-4, IL-5 and IL-13 in BALF, Penh value and lung tissue injury score, and a downregulation of Claudin-2 expression while an upregulation of ZO-1 and Occludin expressions. In addition, the airway inflammation and injury, and the expressions of ZO-1, Occluding and Claudin-2 expressions were found with no statistic differences between TRPA1-/--OVA group and TRPA1-/--OVA + CS group. These results suggest that CS has aggravated the airway inflammation, pathological damage and destruction of TJs in airway epithelium of OVA-induced asthmatic mice, the processes of which are related to the increase of TRPA1 expression.

Prevalence and genetic-phenotypic characteristics of patients with USH2A mutations in a large cohort of Chinese patients with inherited retinal disease.

AIMS: To investigate the frequency of USH2A mutation and the clinical and genetic differences between Usher syndrome type II (USH2) and retinitis pigmentosa (RP) in a large cohort of Chinese patients. METHODS: A total of 1381 patients with inherited retinal disease (IRD) were recruited. The phenotypic and genotypic information of patients with USH2A mutations was evaluated. RESULTS: The prevalence of patients with USH2A mutations was 15.75%, which was the most frequently detected gene in this cohort of patients. Hotspot of USH2A mutations was c.8559-2A >G and c.2802T >G. Patients with USH2 had an earlier and more serious decline of visual function and damage to retina structure than did patients with RP in the first 10 years (p<0.05), but there was no difference in the visual prognosis between the two groups when the course of disease exceeded 10 years (p>0.05). Missense variants had less severe consequences and were found more commonly in RP, whereas more deleterious genotypes were associated with an earlier onset of disease and were found more commonly in USH2. CONCLUSIONS: This study provides detailed clinical-genetic assessment of patients with USH2A mutations of Chinese origin, enabling precise genetic diagnoses, better management of these patients and putative therapeutic approaches.

Absolute reduction of peripheral regulatory T cell in patients with relapsing polychondritis.

OBJECTIVES: Although relapsing polychondritis (RP) is considered as an immune-mediated systemic disease, the levels of peripheral lymphocyte subpopulations are rarely studied in patients with RP. In this study, we focused on changes of peripheral CD4+T cell subsets in patients with RP. METHODS: Absolute numbers and percentages of CD4+T cell subsets including helper T(Th)1, Th2, Th17 cells and regulatory T (Treg) cells in peripheral blood (PB) from 19 RP patients, healthy controls and RA patients respectively were assessed by flow cytometry combined a microbead-based single-platform method. We compared the CD4+T cell levels in all RP patients and healthy controls. In addition, we analysed the difference of the absolute number and percentage of Treg cells between RP and RA patients. RESULTS: Compared with healthy controls, all RP patients had significantly both lower absolute number and proportion of Treg cells (absolute number, 45.10/µl vs. 22.48/µl, p<0.001; proportion, 5.19% vs. 3.78%, p<0.001) no matter whether they had received treatment or not. Similarly, the absolute number of Th2 cells in all RP patients was decreased (10.19/µl vs. 7.44/µl, p=0.030). However, there were no significant differences in percentages and absolute numbers of Th1 and Th17 cells between RP patients and healthy controls. The above results led to increased ratios of Th1/Treg (3.68 vs. 2.06, p=0.020), Th2/Treg (0.29 vs. 0.21, p=0.037) and Th17/Treg (0.25 vs. 0.14, p<0.001) in RP patients, and untreated RP patients were mainly characterised by the imbalance of Th17/Treg (0.25 vs. 0.14, p<0.01). There was no significant difference in Treg cells between RP and RA patients (p>0.05). CONCLUSIONS: Our data suggest that the reduction of Treg cells and its imbalance with Th cells play an important role in the pathogenesis of RP.

Comprehensive analysis of genetic and clinical characteristics of 30 patients with X-linked juvenile retinoschisis in China.

PURPOSE: To provides the clinical and genetic characteristics of a series of Chinese patients with X-linked juvenile retinoschisis (XLRS) through multimodal imaging and next-generation sequencing. METHODS: Thirty patients (60 eyes) from 29 unrelated families of Chinese origin with XLRS were screened using multigene panel testing, and underwent a complete clinical evaluation. All variants identified in this study and reported in the Human Gene Mutation Database were analysed. RESULTS: Twenty-five distinct variants in the retinoschisin gene were identified, of which eight were novel, and one was de novo. Missense mutations were the most prevalent type, and mutation hot spot was localized in the discoidin domain. The mean Snellen best-corrected visual acuity was 0.28 ± 0.17. Of all eyes presenting with schisis, 92.86% had lamellar schisis and 62.5% had peripheral schisis. Schisis changes mostly involved inner and outer nuclear layers. X-linked juvenile retinoschisis (XLRS) patients had a high incidence of complications, and peripheral schisis was a risk factor for it. No obvious genotype-phenotype association was observed. CONCLUSION: This study provides comprehensive analyses of the genetic and clinical characteristics of XLRS in a cohort of Chinese patients. The fourth de novo mutation in RS1 was identified. And we show that XLRS has a wide spectrum of clinical characteristics; hence, molecular diagnosis is crucial for its diagnosis, differential diagnosis and genetic counselling. Peripheral schisis is a risk factor for the high incidence of complications, and no clear genotype-phenotype correlations were found.

Novel variants of ABCA4 in Han Chinese families with Stargardt disease.

BACKGROUND: Stargardt disease (STGD1) is a common recessive hereditary macular dystrophy in early adulthood or childhood, with an estimated prevalence of 1:8000 to 1:10,000. ABCA4 is the causative gene for STGD1. The current study aims at identifying the novel disease-related ABCA4 variants in Han Chinese families with STGD1 using next-generation sequencing (NGS). METHODS: In the present study, 12 unrelated Han Chinese families (19 males and 17 females) with STGD1 were tested by panel-based NGS. In order to capture the coding exons and the untranslated regions (UTRs) plus 30 bp of intronic flanking sequences of 792 genes, which were closely associated with usual ophthalmic genetic disease, we designed a customized panel, namely, Target_Eye_792_V2 chip. STGD1 patients were clinically diagnosed by experienced ophthalmologists. All the detected variants were filtered and analyzed through the public databases and in silico programs to assess potential pathogenicity. RESULTS: Twenty-one ABCA4 mutant variants were detected in 12 unrelated Han Chinese families with STGD1, containing 14 missense, three splicing, two frameshift, one small deletion, and one nonsense variants. Base on the American College of Medical Genetics (ACMG) guidelines, 8 likely pathogenic and 13 pathogenic variants were determined. The functional consequences of these mutant variants were predicted through in silico programs. Of the 21 mutant variants in ABCA4, two novel coding variants c.3017G > A and c.5167 T > C and one novel null variant c.3051-1G > A were detected in three unrelated probands. CONCLUSIONS: By panel-based NGS, 21 ABCA4 variants were confirmed in 12 unrelated Han Chinese families. Among them, 3 novel mutant variants were found, which further expanded the ABCA4 mutation spectrum in STGD1 patients.

Cell Development Deficiency and Gene Expression Dysregulation of Trisomy 21 Retina Revealed by Single-Nucleus RNA Sequencing.

Retina is a crucial tissue for capturing and processing light stimulus. It is critical to describe the characteristics of retina at the single-cell level for understanding its biological functions. A variety of abnormalities in terms of morphology and function are present in the trisomy 21 (T21) retina. To evaluate the consequences of chromosome aneuploidy on retina development, we identified the single-cell transcriptional profiles of a T21 fetus and performed comprehensive bioinformatic analyses. Our data revealed the diversity and heterogeneity of cellular compositions in T21 retina, as well as the abnormal constitution of T21 retina compared to disomic retina. In total, we identified seven major cell types and several subtypes within each cell type, followed by the detection of corresponding molecular markers, including previously reported ones and a series of novel markers. Through the analysis of the retinal differentiation process, subtypes of retinal progenitor cells (RPCs) exhibiting the potential of different retinal cell-type commitments and certain Müller glial cells (MGs) with differentiating potency were identified. Moreover, the extensive communication networks between cellular types were confirmed, among which a few ligand-receptor interactions were related to the formation and function of retina and immunoregulatory interactions. Taken together, our data provides the first ever single-cell transcriptome profiles for human T21 retina, which facilitates the understanding on the dosage effects of chromosome 21 on the development of retina.

Mutation Screening of mtDNA Combined Targeted Exon Sequencing in a Cohort With Suspected Hereditary Optic Neuropathy.

Purpose: Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (ADOA) are the two commonest forms of hereditary optic neuropathy. The aim of this study was to comprehensively investigate the incidence and spectrum of mutations in patients with suspected hereditary optic neuropathy by combining mitochondrial DNA (mtDNA) genome-wide and targeted exon sequencing. Methods: A cohort of 1101 subjects were recruited to participate in the study, comprising 177 families (177 probands and their family members, a total of 537 subjects, including 254 patients) and 164 sporadic cases with suspected hereditary optic neuropathy, and 400 unrelated control subjects for genetic analysis: all subjects (including control subjects) underwent a comprehensive ophthalmologic examination and were subjected to sequencing analysis of mtDNA genome-wide and targeted exon. Overall, targeted exon sequencing was used to screen 792 genes associated with common hereditary eye diseases, and the mtDNA genome-wide were screened by next-generation sequencing. Results: We found variants detected in 168 (40.2%, 168/418) of the 418 patients screened. Among these, 132 cases (78.6%, 132/168) were detected with known LHON disease-causing mtDNA variants; 40 cases (23.8%, 40/168) were detected with nuclear DNA (ntDNA) variants, which included 36 cases (21.4%, 36/168) with detected OPA1 mutations, 4 patients (2.4%, 4/168) with detected OPA3 mutations, and 2 patients (1.2%, 2/168) with detected TMEM126A homozygous mutation. Coexistence variation (mtDNA/mtDNA [n = 16], ntDNA/ntDNA [n = 4], mtDNA/ntDNA [n = 7]) was found in 27 patients (16.4%, 27/165), including mtDNA/ntDNA coexistence variation that was detected in seven patients. Among these ntDNA mutations, 38 distinct disease-causing variants, including autosomal recessive heterozygous mutations, were detected, which included 22 novel variants and two de novo variants. Total haplogroup distribution showed that 34.5% (29/84) and 28.6% (24/84) of the affected subjects with m.11778G>A belonged to haplogroup D and M, with a high frequency of subhaplogroups D4, D5, and M7. Conclusions: The LHON-mtDNA mutations are the commonest genetic defects in this Chinese cohort, followed by the OPA1 mutations. To our knowledge, this is the first comprehensive study of LHON, ADOA, and autosomal recessive optic atrophy combined with mtDNA genome-wide and targeted exon sequencing, as well as haplogroup analysis, in a large cohort of Chinese patients with suspected hereditary optic neuropathy. Our findings provide a powerful basis for genetic counseling in patients with suspected hereditary optic neuropathy. Translational Relevance: We applied mtDNA genome-wide sequencing combined with panel-based targeted exon sequencing to explore the pathogenic variation spectrum and genetic characteristics of patients with suspected hereditary optic neuropathy, providing a comprehensive research strategy for clinical assistant diagnosis, treatment, and genetic counseling.

Next-generation sequencing-based clinical diagnosis of choroideremia and comprehensive mutational and clinical analyses.

BACKGROUND: To report the clinical and genetic findings from seven Chinese patients with choroideremia. METHODS: Five hundred seventy-eight patients with a clinically suspected diagnosis of retinitis pigmentosa (RP) underwent comprehensive ophthalmic examinations. Next-generation sequencing (NGS) was performed on samples from all patients. Detailed clinical characteristics of the patients with choroideremia identified in this study were assessed using multimodal imaging. RESULTS: Seven patients with choroideremia were identified, and six novel variants in CHM (c.1960 T > C p.Ter654Gln, c.1257del p.Ile420*fs1, c.1103_1121delATGGCAACACTCCATTTTT p.Tyr368Cysfs35, c.1414-2A > T, and c.1213C > T p.Gln405Ter, c.117-1G > A) were revealed. All variants were deleterious mutations: two were frameshifts, two were nonsense mutations, two were splicing mutations, and one was a readthrough mutation. The clinical phenotypes of these patients were markedly heterogeneous, and they shared many common clinical features with RP, including night blindness, constriction of the visual field and gradually reduced visual acuity. However, patients with choroideremia showed pigment hypertrophy and clumping, and chorioretinal atrophy, and a majority of patients with choroideremia presented with retinal tubulations in the outer layer of the retina. CONCLUSIONS: We provide a detailed description of the genotypes and phenotypes of seven patients with choroideremia who were accurately diagnosed using NGS. These findings provide a better understanding of the genetics and phenotypes of choroideremia.

Panel-based targeted exome sequencing reveals novel candidate susceptibility loci for age-related cataracts in Chinese Cohort.

BACKGROUND: Age-related cataracts (ARC) is the most common blinding eye disease worldwide, and its incidence tend to become younger. However, the relationship between genetic factors and mechanisms is not fully understood. The aim of the study was to further clarify the relationship between ARC and genetic mechanisms in East Asian populations and to elucidate the pathogenesis. METHODS: The study collected 191 sporadic cataracts and 208 healthy people from the eastern provinces of China, with an average age of about 60 years. All participants were subjected to a comprehensive ophthalmic clinical examination and peripheral blood samples were collected and their genomic DNA was extracted. Mutations were screened among 792 candidate genes to enhance understanding of the disease through targeted capture and high-throughput sequencing. RESULTS: We identified novel candidate susceptibility gene, which may serve as a potential susceptibility factor leading to an increase in the incidence of age-related cataracts. Three novel loci are associated with age-related cataracts significant significance: rs129882 in DBH (p = 5.27E-07, odds ratio = 3.9), rs1800280 in DMD (p = 2.85E-06, odds ratio = 1.4) and rs2871776 in ATP13A2 (p = 4.18E-05, odds ratio = 0.04). Gene-gene interaction analysis revealed that the most significant interactions between genes include the interaction between DBH and TUB (rs17847537 in TUB, rs129882 in DBH, p-value = 2.12E-14), and the interaction between DBH and DMD (rs1800280 in DMD, rs129882 in DBH, p-value = 2.12E-14). Pathway analysis shows that the most significant processes are concentrated in response to light stimulation (adjusted p-Value = 5.56E-03), response to radiation (adjusted P-Value = 5.56E-03), abiotic stimulus (adjusted p-Value = 5.56E-03). eQTL analysis shows that DBH rs129882 could regulate the expression of DBH mRNA in various tissues including retina. CONCLUSION: Our study indicates rs129882 and rs1800280 loci are associated with age-related cataracts, which enlarge the gene map of age-related cataracts.

Clinical and Genetic Characteristics of Chinese Patients with Occult Macular Dystrophy.

Purpose: To investigate the clinical and genetic characteristics of occult macular dystrophy (OMD) based on a Chinese patient cohort. Methods: Fifteen Chinese OMD patients from nine unrelated families underwent genetic testing, and all of them harbored a pathogenic RP1L1 variant. Comprehensive ophthalmic examinations were performed in nine probands, including spectral-domain optical coherence tomography (SD-OCT), near-infrared reflectance (NIR), fundus autofluorescence (AF), and multifocal electroretinography. Results: The RP1L1 variants p.R45W and p.S1199C were identified in 13 patients and two patients, respectively, and one was a de novo mutation. Among the nine probands, the median ages at onset and examination were 25.0 years (range, 6-51 years) and 27.0 years (range, 14-55 years), respectively. The median decimal visual acuity was 0.20 (range, 0.04-0.5). Foveal photoreceptor thickness and visual acuity showed a significant correlation (r = 0.591; P = 0.01). All eyes presented with an absent interdigitation zone and blurred ellipsoid zone of photoreceptors when examined by SD-OCT. In addition, central round lesions with low NIR reflectance were observed in 66.7% (12/18) of eyes by NIR reflectance imaging, corresponding to the regions with abnormal photoreceptor microstructures observed by SD-OCT. Of the 18 eyes, only four eyes showed ring-like faint hyperfluorescence around the macula by AF. Conclusions: To the best of our knowledge, this is the largest study in a cohort of Chinese OMD patients with RP1L1 mutations. Our findings revealed that the two recurrent RP1L1 variants are related to OMD in the Chinese population. Furthermore, multimodal imaging combined with genetic testing is valuable for diagnosing and monitoring OMD progression.