Publications by authors named "Hoai Viet Tran"

Introduction: The (guanine nucleotide-binding protein, β1) gene encodes for the ubiquitous β1 subunit of heterotrimeric G proteins, which are associated with G-protein-coupled receptors (GPCRs). mutations cause a neurodevelopmental disorder characterized by a broad clinical spectrum. A novel variant has recently been confirmed in a case of rod-cone dystrophy.

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Article Synopsis
  • * Bi-allelic mutations in SAMD7 cause autosomal-recessive macular dystrophy, with some mutations impacting splicing and others affecting its role in repressing CRX-dependent gene activity.
  • * SAMD7 is found in the nuclei of retinal rod and cone cells, highlighting its important role in human retinal function and suggesting differences in the function of SAMD7 between humans and mice.
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Introduction: Mutational screening of inherited retinal disorders is prerequisite for gene targeted therapy. Our aim was to report and analyze the proportions of mutations in inherited retinal disease (IRD)-causing genes from a single center in Switzerland in order to describe the distribution of IRDs in Western Switzerland.

Methods: We conducted a retrospective study of patient records.

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Retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) are two groups of inherited retinal diseases (IRDs) where the rod photoreceptors degenerate followed by the cone photoreceptors of the retina. A genetic diagnosis for IRDs is challenging since >280 genes are associated with these conditions. While whole exome sequencing (WES) is commonly used by diagnostic facilities, the costs and required infrastructure prevent its global applicability.

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Inherited retinal dystrophies (IRD) are due to various gene mutations. Each mutated gene instigates a specific cell homeostasis disruption, leading to a modification in gene expression and retinal degeneration. We previously demonstrated that the polycomb-repressive complex-1 (PRC1) markedly contributes to the cell death process.

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Background: Whereas crystals deposit in the retina, the cornea and limbus in Bietty corneo-retinal dystrophy (BCD) is now well established and documented, only two published cases report their findings in the lens and no cases deep in the lens cortex.

Material And Methods: Four consecutive adult patients from three different unrelated families presenting lens crystals associated with advanced genetically confirmed BCD were enrolled with advanced disease and long follow up (>12 years). Demographics, visual acuity, slit lamp biomicroscopy, lens and posterior pole photography, optical coherence tomography (OCT), autofluorescence, and screening for CYP4V2 type of mutation were performed.

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Retinal dystrophies (RD) are a group of Mendelian disorders caused by rare genetic variations leading to blindness. A pathogenic variant may manifest in both dominant or recessive mode and clinical and genetic heterogeneity makes it difficult to establish a precise diagnosis. In this study, families with autosomal dominant RD in successive generations were identified, and we aimed to determine the disease's molecular origin in these consanguineous families.

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Purpose: RPE65-associated retinal dystrophy (RPE65-RD) is an early onset, progressive, severe retinal dystrophy. We sought to characterize the natural history of retinal degeneration in affected individuals.

Methods: We performed cross-sectional and longitudinal quantitative and qualitative assessments of retinal architecture in RPE65-RD using spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) imaging.

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Article Synopsis
  • Retinitis pigmentosa (RP) affects millions globally, and understanding the genetic causes like PDE6Β mutations is vital for targeted therapies and patient care.
  • Three specific patients with unique PDE6Β mutations were studied, all of whom exhibited early symptoms such as night blindness and progressive vision loss, confirming the need for genetic testing in similar cases.
  • Awareness of PDE6Β mutations is crucial, especially as clinical trials for genetic treatments are underway, providing hope for effective interventions in the future.
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Purpose: The purpose of this study was to investigate fundus autofluorescence lifetimes in patients with choroideremia and to identify tissue-specific lifetime characteristics and potential prognostic markers.

Methods: Autofluorescence lifetimes of the retina were measured in two spectral channels (498-560 nm and 560-720 nm) in patients with choroideremia and age-matched healthy controls. Furthermore, autofluorescence intensities and spectral-domain optical coherence tomography (OCT) data were acquired and compared to fundus autofluorescence lifetime data.

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NR2E3 encodes the photoreceptor-specific nuclear hormone receptor that acts as a repressor of cone-specific gene expression in rod photoreceptors, and as an activator of several rod-specific genes. Recessive variants located in the ligand-binding domain (LBD) of NR2E3 cause enhanced short wavelength sensitive- (S-) cone syndrome (ESCS), a retinal degeneration characterized by an excess of S-cones and non-functional rods. We analyzed the dimerization properties of NR2E3 and the effect of disease-causing LBD missense variants by bioluminescence resonance energy transfer (BRET(2) ) protein interaction assays.

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Leber Congenital Amaurosis (LCA) and Early Childhood Onset Severe Retinal Dystrophy are clinically and genetically heterogeneous retinal disorders characterised by visual impairment and nystagmus from birth or early infancy. We investigated the prevalence of sequence variants in AIPL1 in a large cohort of such patients (n = 392) and probed the likelihood of disease-causation of the identified variants, subsequently undertaking a detailed assessment of the phenotype of patients with disease-causing mutations. Genomic DNA samples were screened for known variants in the AIPL1 gene using a microarray LCA chip, with 153 of these cases then being directly sequenced.

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Purpose: Most RB1 mutations are unique and distributed throughout the RB1 gene. Their detection can be time-consuming and the yield especially low in cases of conservatively-treated sporadic unilateral retinoblastoma (Rb) patients. In order to identify patients with true risk of developing Rb, and to reduce the number of unnecessary examinations under anesthesia in all other cases, we developed a universal sensitive, efficient and cost-effective strategy based on intragenic haplotype analysis.

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Aim: To prospectively study the intraocular pressure (IOP) lowering effect and safety of the new method of very deep sclerectomy with collagen implant (VDSCI) compared with standard deep sclerectomy with collagen implant (DSCI).

Methods: The trial involved 50 eyes of 48 patients with medically uncontrolled primary and secondary open-angle glaucoma, randomized to undergo either VDSCI procedure (25 eyes) or DSCI procedure (25 eyes). Follow-up examinations were performed before surgery and after surgery at day 1, at week 1, at months 1, 2, 3, 6, 9, 12, 18, and 24 months.

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Defects in the photoreceptor-specific gene encoding aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) are clinically heterogeneous and present as Leber Congenital Amaurosis, the severest form of early-onset retinal dystrophy and milder forms of retinal dystrophies such as juvenile retinitis pigmentosa and dominant cone-rod dystrophy. [Perrault, I., Rozet, J.

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Recently, preliminary results of three clinical gene therapy trials for early onset retinitis pigmentosa--Leber congenital amaurosis--suggested that treating this degenerative retinal disease by gene transfection can be safe and efficient to restore a visual function. The definitive validation of this therapeutic approach depends on the long-term results. The forthcoming availability of gene therapy in ophthalmology prompts the implementation: of 1) recruitment, 2) phenotyping and genotyping of affected patients, 3) and creation of a hereditary retinopathy registry.

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Purpose: To describe an extremely rare association of bilateral circumscribed hemangioma (CCH) in the absence of any other evidence of systemic abnormalities.

Methods: A 43-year-old man was referred to our institution with a diagnosis of probable unilateral hemangioma of the right eye with decreased visual acuity.

Results: Funduscopic examination of both eyes revealed one CCH in each eye.

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Purpose: To describe a previously unreported association between phakomatosis pigmentovascularis (PPV) IIa and primary choroidal melanoma.

Design: Case series.

Participants: Three patients with PPV type IIa and choroidal melanoma.

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The angle closure glaucomas are a diverse group of disorders characterized by mechanical blockage of the trabecular meshwork by the peripheral iris leading to elevated intraocular pressure and glaucoma. Understanding the pathophysiologic mechanisms underlying these disorders is essential for both diagnosis and management. This review covers the anatomy, etiology, classification, and therapy of the various angle closure glaucomas and the role that ultrasound biomicroscopy has played in helping us understand these diseases.

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Objective: To evaluate the high-frequency B-scan ultrasonographic characteristics of squamous conjunctival neoplasia (conjunctival intraepithelial neoplasia and squamous cell carcinoma).

Methods: Each of 11 patients was examined with 20- and/or 50-MHz ultrasonography in a retrospective consecutive case series.

Main Outcome Measures: Ultrasonographic findings with clinical and histopathologic correlations.

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